单项选择题
0ur bosun is（）lookout on the forecastle now.
A.at B.in C.for D.on
单项选择题 0ur engine has a（）of 10000 horse-power.
单项选择题 0ur jumbo boom（）out of use for a long time.
单项选择题 0ur jumbo boom can（）20 tons.
