下列材料中， 的焊接性最好。
A. 铸铁
B. 铝合金
C. 低碳钢
D. 高合金钢
-Have you seen the film Lost In Thailand?-Oh,no.I my homework all day yesterday.
A. had done
B. did
C. have done
D. was doing
Nothing but some ancient Chinese coins in the sunken ship since they began the exploration.
A. has found
B. has been found
C. had been found
D. have been found
-What happened to Bill?-He really fast when suddenly he ran into a parked car.
A. had run
B. was running
C. has run
D. has been running
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