问题补充:
We can work out the physics problem. Can you tell us ?
A. how to do
B. what to do it
C. how to do it
D. what should to do
答案:
A. how to do
B. what to do it
(答案→)C. how to do it
D. what should to do
解析:疑问词后接动词不定式。句意“我们不能算出这个物理难题,你能告诉我们怎样算出来”,what可作为do的宾语,how不可作为do的宾语,因此后需加代词it,因此选C。