—How’s your tour around the North Lake? Is it beautiful?—It be but it is now heavily po

问题补充：

—How’s your tour around the North Lake? Is it beautiful?

—It be, but it is now heavily polluted.

A. will

B. would

C. should

D. must

答案：

A. will

B. would

(答案→)C. should

D. must

解析：it should be后承前省略了beautiful一词，即指应该是很美的，但由于受到了严重的污染，所以不美了。