He looks upset. He doesn’t know _______

试题详情及答案解析

He looks upset. He doesn’t know ________.

A．what to do it	B．how to do it
C．how to do	D．do what

答案：B

试题分析：句意：他看起来很伤心。他不知道如何去做。分析：what to do中what做动词do 的宾语；how to do it中how为it 的方式。明确第二项正确。故选B
考点：考查疑问词+不定式。