1. engage： vi.从事于，参加。

　　固定搭配：engage in.e.g. He is engaged in politics.他从事政治。

　　be engaged to：使订婚，约定。 e.g. She was engaged to that handsome boy.她和那个英俊的男孩订婚了。

　　2. scarcely： adv. 几乎不，几乎没有。

　　固定搭配：scarcely…when…一…就…，可引导时间状语从句，只用于过去时，主句动作发生在从句动作前，故用过去完成时，如果scarcely用于句首，主句的主谓部分应倒装。

　　e.g. Scarcely had Jack seen me when he left the room.杰克刚见到我就离开了屋子。

　　3. unlike： prep. 不像，和…不同。区别dislike， v.厌恶，讨厌

　　词组：

　　1. a great deal ： 许多，大量

　　用法：用于不可数名词前。例：She spent a great deal of money on clothes. 她花了很多钱买衣服。

　　相关短语： a great many of 许多，大量 （可数名词前）

　　a large number of 大量，许多 （可数名词前）

　　a lot of 许多 （可数名词或不可数名词前）

　　a large quantity of 许多，大量 （不可数名词前）

　　2. take care of ： 照顾，照料

　　例：The young couple hired a babysitter to take care of their baby. 这对年轻夫妇雇了一个保姆为他们照看婴儿。

　　（视频）

　　三、Text B重点句子：（句子下面的解释同划线部分链接）

　　1. The ants， hardworking as they are， have their times for play. （P126，Para2，L2） 蚂蚁虽然勤于工作，但仍有时间玩耍。此句中as 引导了让步状语从句，句子要倒装。

　　2. The parrot learns to talk， though in some other respects it is quite stupid. （P126，Para5，L2） 鹦鹉虽然在其他方面很笨，但它会说话。

　　3. Though animals think and learn， they do not make any real improvement in their ways of doing things. （P127，Para2，l1）

　　虽然动物会思考和学习，但它们不能在做事的方式上像人一样做出真正的变革。

　　4. They are said to do such things by instinct. （P127，Para3，L3）据说它们凭着本能来做这些事情。

　　5. It is by this instinct that birds build their nests. （P127，Para3，L4） 正是通过这种本能，鸟类筑巢。

　　6. If he had had his wits about him， he would have known that there was no use in building a dam where there was no water. （P127，Para4，L7） 如果它真有头脑的话，它本应知道在没有水的地方建筑堤坝是没有用的。

　　此句用了虚拟语气，与过去事实相反的假设。主句用would + have done 的形式，从句用had done 的形式。（停顿）

　　注意：将P124和P133及P138练习精练并准确翻译。（可以加个叹号并用其它颜色标出放在下面）

　　（视频）

　　四：试题分析及自测：

　　1. No one has been able to prove that fish is ____ better for the brain than many other kinds of food.

　　A. some B. so C. as D. any

　　答案为D. 考点是不定代词any . any better 指任何好处。

　　2. Tomatoes were once called love apples and were supposed to make those who ate them _____ in love.

　　A. fell B. feel C. fall D. felt

　　答案是C. 考点是固定词组fall in love 坠入爱河。注意两组词的词形辨析：

　　fall ， fell ， fallen ； feel ， felt ， felt

　　3. Washing food down with water as a ______ for chewing is not a good habit.

　　A. direction B. substitute C. possibility D. resource

　　答案是B. 考点是as a substitute for ： 作为… 的代替物。

　　4. A few years ago the belief became generally accepted _____ orange juice and milk should never be drunk at the same meal.

　　A. which B. that C. how D. why

　　答案是B. 考点是that 引导的同位语从句，先行词是belief.此句中become general 提前是为了保持句子平衡。

　　5. 汉译英：据说有些吃鹿肉的原始人能跑得像鹿一样飞快。

　　答案： It was said that some primitive people who ate deer could run as fast as the deer. （本单元视频结束）

　　6. for their help， we would not have succeeded. （04，4）

　　A.Hadn‘t been B. Had it not been C. It hadn’t been D. Had been not

　　答案：B.

　　7.There was so much noise that the teacher couldn‘t make . （04，4）

　　A. himself to hear B. to hear himself C. himself hear D. himself heard

　　答案：D.此句型为make oneself done，区别make sb. do.

　　8.All the food that （keep） our bodies strong was once in the vegetable form.

　　答案：keeps.

　　9.By the time a baby has reached his first birthday， he should， without the help of an adult， sit up or even stand up.

　　A. to be able to B. able to C. to be able D. be able to

　　答案：D.

　　10.Many birds will， in the normal course of their migration， flying more than three thousand miles

　　A B C

　　to reach their winter homes.

　　D

　　答案：B，改为fly.

　　11.When the weather becomes colder we know that the air mass must originated in the Arctic

　　A B C

　　rather than over the Gulf of Mexico.

　　D

　　答案：C，改为must have originated.

　　12.The general public a large number of computers now， because prices are beginning to decrease.

　　A. must buy B. must have bought C. must be buying D. must buying

　　答案：C.

　　13.The American buffalo must be reproduce itself again because it has been removed from the

　　A B C D

　　endangered species list.

　　答案：A.改为must be reproducing.

　　14.Since more than 50 percent of all marriages in the United States and in spanorce， about half of the children in America must in single-parent homes.

　　A. grow up B. to grow up C. growing up D. have grow up

　　答案：A.

　　15.Sheep must have mate in fall since the young are born in early spring every

　　A B C D

　　year.

　　答案：B.改为must mate.