英语单选题,1.Let's play football after school.Sorry,I can't play

英语单选题,
1.Let's play football after school.
Sorry,I can't play with you.I'll get my hair( ）
A.cut B.to cut C.cutting D.be cut
2.Last year my uncle has an opportunity( )abroad,but he gave it up
A.study B.to study C.of study D.for studying
3.National Day is coming,and we'll have seven days ( )
A.up B.down C.on D.off
4.It was raining hard,but the workers kept ( ）on the rain
A.works B.to work C.working D.work
最好能说下原因 主要我们还没上过.