关于英语情态动词和虚拟语气，如图，第8题，请解释为什么选B及其他三项不选的理由

Question

如题所述

Answer 1

1- It can't have been him - It must have been Mr.Li 2 第二题不清楚，看不清 3 - He might have been ill 4 It could't have rained last night 5 He would have arrived there 6 We meant to have. 7 You should / ought to have invited me
英语,情态动词\虚拟语气,三项,理由
1- It can't have been him - It must have been Mr.Li 2 第二题不清楚，看不清 3 - He might have been ill 4 It could't have rained last night 5 He would have arrived there 6 We meant to have. 7 You should / ought to have invited me追问

？我是想问第8题

Answer 2

since是因为的意思，其实根据语意便可选出答案。因为没有人给他任何帮助，他只能靠他自己去做这一项调查。只能 表明选must本回答被提问者采纳