---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
网友回答
A. will
B. would
(答案→)C. should
D. must
解析：should意为“应该”。根据所提供的情景“but it is now heavily polluted”可判断出它应该是美丽的。will作情态动词意为“愿意”；would意为“愿意”；must意为“必须”。