Question

8. They were walking along the shore a huge wave appeared out of nowhere,sweeping them out to sea.

   A. as   B. while   C. when   D. though

Answer 1

8. C

8. C解析:句意:他们正沿着岸边走，这时 一个不知从何处来的巨浪扑过来，把他们 冲到海里去了。

be doing…when…“正在 做……这时……”，为固定结构，其余选项 不合语境。