问题
单项选择题
On the forecastle deck,the chief officer and the bosun（）sharp lookout.
A.to keep
B.are keep
C.is keeping
D.are keeping
答案
参考答案：D
搜题请搜索小程序“爱下问搜题”
On the forecastle deck,the chief officer and the bosun（）sharp lookout.
A.to keep
B.are keep
C.is keeping
D.are keeping
参考答案：D