It was not until the entire river was covered with rotten fish which died from acid rain that ____ how serious the pollution was.
A.did the villagers realize B.made the villagers realize
C.the villagers realized D.realized the villagers.
____ they went abroad, the tourists were so curious about everything that they couldn’t help purchasing many goods, which made it difficult to control the budget.
A.For the first time B.By the first time
C.At the first time D.The first time
____ the class teacher put emphasis on the importance of doing homework independently, his students still spent most of the time copying others’ homework.
A.While B.Despite
C.Unless D.Once
_____ we are faced with, we will have no choice but to unite and overcome them.
A.However tremendous difficulties
B.However tremendous some difficulties
C.Whatever tremendous difficulties
D.Whatever tremendous the difficulties
The efforts made by researchers ____ possible the appearance of a new life-saving medicine.
A.were made B.made
C.made it D.were made it
Have you ever heard such stories about those loyal dogs ____ in this book?
A.as they are described B.that they are described
C.as are described D.that are described
