问题

Scientists _______ a lot of experiments on animals, hoping to find and effective way to cure the patients who had AIDS.

A:carried on
B:carried out
C:carried away
D:carried off

正确答案是：

同类题型

.How often do you go to see yourparents— __________.

_____ many other developingcountries, has suffered the misery of war and experienced major changes overthe last 100 years

________ notebook is that—It is Jim’s.He put it here just now.

How was your last day off ––_______. It was windy and cloudy all day.

_____ on the top of the hill is a monument, dating back to hundreds of years ago.