1.He must have had an accident ,or ___ then.A.would have been here B.had to be here C.should be here D.would be here 2.He walked in the street without ____ to buy anything .A.intention B.purpose C.heart D.thought 3.The scientist is several years junior ___ Mr.Smith.A.than B.to C.for D.on 请翻译,并解析为什么!

1.He must have had an accident ,or ___ then.
A.would have been here
B.had to be here
C.should be here
D.would be here
2.He walked in the street without ____ to buy anything .
A.intention B.purpose C.heart D.thought
3.The scientist is several years junior ___ Mr.Smith.
A.than B.to C.for D.on
请翻译,并解析为什么!