问题
选择题
As nobody here knows what is wrong with the machine, we send for an engineer to handle the problem．
A．should
B．must
C．can
D．would
答案
答案：B
考查情态动词。should 应该，must 必须，can 能，would 会，句意：因为在这没有人知道这台机器怎么了，我们必须派人请一个工程师来处理这个问题。所以选B。