一、用所给词的适当形式填空。
1. To keep the air clean, we should
plant
(plant) more trees.
2. We shouldn't
drive
(drive) so much, because cars use a lot of energy.
3. Look! The man
is smoking
. He shouldn't
smoke
in public places. (smoke)
答案：1. plant 2. drive
3. is smoking, smoke
1.
Should
I take care of
my
little brother when you go out?
2. You
shouldn't finish
your homework first.
3.
What
should I
do
before the meal?
答案：1. Should，my
2. shouldn't finish
3. What，do
1. 有情态动词的句子变成一般疑问句,把情态动词提前，注意人称的对应变化，故填Should，my。
2. 有情态动词的句子变成否定句,在情态动词后面加 not,故填 shouldn't finish。
3. 询问应该做什么用“What should ... do ... ?”，注意句首字母要大写,故填 What，do。
