Jim, it’s so late . are you busy with— My homework.. If I don’t finish it, my teacher will be angry with me.

Tom didn’t give up studying ________________ he failedmany times.

My sister was against my suggestion while my brother was________it.[ ]

There’re more than 100 elements found in nature, ______ are metals.

David said that it was______ his strong interest in literature_____ he chose the course.