课时作业(五) [必修1 module 5 a lesson in a lab] [限时：35分钟] ⅰ.单项填空 1．you ________ this， mother. it's no concern of yours. a．keep to b．keep out of c．keep off d．keep up 2．—do you mind if i smoke？ —________ a．why not？ b．yes， help yourself. c．go ahead. d．yes， but you'd better not. 3．we all sat with plates ________ on our knees. a．to be balanced b．balanced c．balancing d
