完成句子(10小题，每空1分，共17分)
_______ _______ (由……组成) 6 members, my group is the best in our class.
Don’t leave your skin _______ _______ (暴露于) the sun for too long or you will get sunburnt.
The teacher _______ _______ (继续) the lesson where he left off yesterday.
He didn’t propose to her _______ _______ of (因为缺乏) courage.
When seeing off his mother, Tom waved until he _______ _______ _______ (看不见)the train.
I’ve developed the habit of _______ _______ (集中) my study.
With her help, I finished the work _______ _______ (提前)time.
Whether we can go for a picnic _______ _______ (取决于) the weather.