—Guys,Iwasreallywornout!Ican'twalkanyfurther!—Weshouldh...

問題詳情：

— Guys, I was really worn out! I can't walk any further!

— We should have a rest. We ________ the cave a whole day.

A. exploring　　  B. are exploring　   C. have been exploring　   D. explore

【回答】

C

知識點：動詞時態與語態

題型：選擇題