【多选题】Mark Twain had led an active life in the very center of the American experience. He had been a____________ .
A.
printer, pilot, soldier
B.
silver-minor, gold-washer
C.
lecturer, traveler, businessman
D.
novelist, autobiographer
【简答题】链传动的类型为传动链传动、()、牵引链传动。
【单选题】Few people believed the dam had been burst because there had been too many false alarms.
【多选题】链传动的类型为传动链传动、()链传动、()链传动。
【简答题】链传动的类型为()链传动、()链传动、()链传动。
【单选题】Fewer people would have died if______.
A.
more announcements had been made
B.
people hadn't used the lifts
C.
the people had obeyed the office
D.
the incident had happened on a weekend
【简答题】链传动的类型为传动链传动、起重链传动、()。