he always wondered -------- and asked his mother a lot of questions

题目

he always wondered -------- and asked his mother a lot of questions
1.how did things work
2.how things work
3.how things worked
4.how worked the things are
说一下原因,为什么选他

答案

选3.
1是疑问句语序,而从句应是陈述句语序
2时态有误,应该是一般过去时
4有些混乱= =,首先,特殊疑问词后接动词应用动词不定式,再者,那个be动词是怎么冒出来的?