In the experiment we kept a watchful eye ________ the development and recorded every detail

I don’t doubt that the price of thered apples is higher than___________ of the yellow__________ in this area.

Have you been here before?—- This is the second time I ______to the Great Wall

There are ________ approaches to English teaching.But not all of them are equally efficient forour Chinese students. [ ]

I’m afraid I can only make a small contributionthis time— __________ We really appreciate your assistance