Now there is a danger ________ the ground may fall in under the heavy traffic.

Now there is a danger ________ the ground may fall in under the heavy traffic.

1. A.
   whether
2. B.
   if
3. C.
   X
4. D.
   that

Now there is a danger ________ the ground may fall in under the heavy traffic.

A. whether            B. if                  C. X             D. that

Now there is a danger ________ the ground may fall in under the heavy traffic.

Now there is a danger ________ the ground may fall in (沉下) under the heavy traffic.

A. whether

B. if

C. X

D. that