When the boy couldn't find his mother,he didn't knowA．what to do B．how to do C．what to do it D．how to do it 要有解析
问题描述：
When the boy couldn't find his mother,he didn't know
A．what to do B．how to do C．what to do it D．how to do it 要有解析
答
正选A
b中how to do ，do没有宾语
c中 what to do it ，do不可以有宾语it，或者改成 do with it
d中 how to do it ，语义不通！
答
B.how怎麽样
答
正选A
b中how to do ,do没有宾语 how 不能做宾语
c中 what to do it ,do的宾语重复 it 和what
d中 how to do it ,怎样做这件事 语义不通
重点 do 是及物动词
答
A
当那个男孩找不到他妈妈时，他不知道该做什么