1,You will ___clean your own boots when your jion the army.\

1,You will ___clean your own boots when your jion the army.\
A.have B,have to C,must
2Another important difference is ___the students in Taiwan have many school.
A,THAT B,WHO C,WHEN
5They claim that this engine is _____ the previous one.
A,twice as powerful as B,as twice powerful as C,powerful as twice as D,twice powerful as
6,If Dorothy had not been badly hurt in a car accident,____in the last month's race.
A,she would participate B,she participated C,she would have participated D,she will have participate