Question

We can't 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

Answer 1

C

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。