Thevoyagesoftravellersbeforethe17thcenturyshowthatthey...

问题详情：

 The voyages of travellers before the 17th century show that they were not ________ the sea even though they didn’t have modern navigational aids.

   A.  at the expense of    B.  at the risk of       C.  in the way of    D.  at the mercy of 

【回答】

知识点：词组 短语

题型：选择题