Nobodyknowshowpeoplefirstcametotheseislands.They

问题详情：

 Nobody knows how people first came to these islands. They ______ from South America on rafts.

A. must have sailed　　               B. can have sailed　　

C. might have sailed　　              D. should have sailed

【回答】

C

知识点：虚拟语气与情态动词

题型：选择题