如果3个连续偶数中，m为最小的偶数，则这3个数的和为 _________ ．
3m+6
银行汇票自出票之日起，付款期限最长不得超过( )。
A．1个月
B．2个月
C．3个月
D．4个月
Some scientists think that it will take __ of years to make robots do most work for humans.
A. hundreds B. hundred C. thousand
