昨天小练习的答案：
1. f 2. d 3. b 4. g 5. h 6. c 7. e 8. a
今天将学习JECT和TRACT两个词根~
JECT. 源自拉丁动词jacere, 意为:"throw" or "hurl". To reject something is to throw (or push) it back; to eject something is to throw (or drive) it out; to inject something is to throw (or squirt) it into something else.
interject. To interrupt a conversation with a comment or remark.
例句：His anger was growing as he listened to the conversation, and every so often he would interject a crude comment.
根据其拉丁词根，interject本意为"throw between". For most of the word's history, however, the only things that have been interjected have been comments dropped suddenly into a conversation. Interjections are often humorous, and sometimes even insulting, and the best interjections are so quick that the conversation isn't even interrupted.
conjecture. To guess.
例句：He was last heard of in Bogota, and they conjectured that he had met his end in the Andes(安第斯山脉) at the hands of the guerrillas(游击队员).
Formed with prefix con-, "together", conjecture means literally "to throw together"--that is, to produce a theory by putting together a number of facts. So, for example, Columbus conjectured from his calculations that he would reach Asia if he sailed westward, and his later conjecture that there was a "Northwest Passage" by sea from the Atlantic to the Pacific over the North American continent was proved correct centuries later.
projection. An estimate(估算) of what might happen in the future based on what is happening now.
例句：The president has been hearing different deficit(赤字，逆差) projections all week from the members of his economic team.
Projection has various meanings, but what they all have in common is that something is sent out or forward. A movie is projected onto a screen; a skilled actress projects her voice out into a large theater without seeming to shout; and something sticks out from a wall can be called a projection. But the meaning we focus on here is the one used by businesses and governments. Most projections of this kind are estimates of a company's sales or profits--or of the finances of a town, state, or country--sometime in the future.
trajectory.(轨迹) The curved(弯曲的，弧形的) path that an object makes in space, or that a thrown object follows as it rises and falls to earth.
例句：Considering the likely range, trajectory, and accuracy of a bullet fired from a cheap handgun at 100 yards, the murder seemed incredible.
Formed with part of the prefix trans-, "across", trajectory means a "hurling across". 如果已知一个物体的运行速度，并通过分析物体受的重力和其它力，能够计算出该物体运行的trajectory. Missiles stand a chance of hitting their target only if their trajectory has been plotted accurately. 这个词大部分用在物理和工程上。在其他地方，比如，人生轨迹、历史轨迹也可以用这个词。
TRACT. 源自拉丁动词trahere, 意为”drag or draw“. Something attractive draws us toward it. Something distracting pulls your attention away. And when you extract something from behind the sofa, you drag it out.
traction.(牵引力，附着摩擦力) The friction(摩擦力) that allows a moving thing to move over a surface without slipping.
例句：The spinning wheels were getting no traction on the ice, and we began to slip backward down the hill.
A tractor is something that pulls something else. We usually use the word for a piece of farm machinery, but it's also the name of the part of a big truck that includes the engine and the cab. Tractors get terrific traction, because of their powerful engines and the deep ridges on their huge wheels. A cross-country skier needs traction to kick herself forward, but doesn't want it to slow her down when she's gliding, so the bottom of the skis may have a "fish-scale" surface that permits both of these at the same time.
retract.(缩回，收回) (1) To pull back (something) into something larger. (2) To take back (something said or written).
例句：She was forced to retract her comment about her opponent after it was condemned in the press.
The prefix re- ("back") gives retract the meaning of "draw back". Just as a cat retracts its claws into its paws when they aren't being used, a public figure may issue a retraction in order to say that he or she no longer wants to say something that just been said. But it's sometimes hard to know what a retraction means: Was the original statement an error or an outright lie?Sometimes a politician even has to retract something that everyone actually assumes is the truth. Thousands of citizens were forced to publicly retract their "wrong" ideas by the Soviet government in the 1930s and the Chinese government in the 1960s. Someone wrongly accused may demand a retraction from his accuser--though today it seems more likely that he'll just go ahead and sue.
protracted.(拖延) Drawn out, continued, or extended.
例句：No one was looking forward to a protracted struggle for custody of the baby.
With its prefix pro-, "forward", protracted usually applies to something drawn out forward in time. A protracted strike may cripple a company; a protracted rainy spell may rot the roots of vegetables; and a protracted lawsuit occasionally outlives the parties involved. Before the invention of the polio vaccines, polio's many victims had no choice but to suffer a protracted illness and its aftereffects.
intractable.(难驾驭的) Not easily handled, led, taught, or controlled.
例句：Corruption in the army was the country's intractable problem, and for many years all foreign aid had ended up in the colonels' pockets.
Intractable simply means "untreatable", and even comes from the same root. The word may describe both people and conditions. A cancer patient may suffer intractable pain that doctors are unable to treat. An intractable alcoholic goes back to the bottle immediately after "drying out". Homelessness, though it hardly existed thirty years ago, is now sometimes regarded as an intractable problem.
Quizzes:
Match the word on the left to the correct definition on the right:
1. pulling force a. protracted
2. assume b. interject
3. expectation c. trajectory
4. difficult d. traction
5. unsay e. conjecture
6. drawn out f. intractable
7. curved path g. retract
8. interrupt with h. projection
