英语选择1.Five minutes earlier,_____ we could have caught the la

英语选择
1.Five minutes earlier,_____ we could have caught the last train.
A.or B.but C.and D.so
2.Johnson knocked at the door _____ I was watching TV.
A.until B.while C.before D.after
3.Zhang Ying gives me more help than _____.
A.Joan is B.Joan gives C.Joan's help D.Joan does
4.Two sisters of _____ helped us paint the house.
A.him B.his C.he D.he's
5.I hope that there are enough eggs for each child to have ____,
A.it B.one C.them D.him
6.That was ______ that I could not work it out.
A.so difficult a problem B.a so difficult problem C.such difficult a problem D.so difficult problem