选A
than was allowed.( = than it was allowed for me to take )
句意:我把手提箱拿去过称,结果发现我带的行李超过了额定重量.
当than作为连词,引导比较状语从句时,相比较的两个部分在结构上应当平行,只是than-从句常为省略句,有时than后直接跟谓动.
She played the piano much better than could have been expected.(省略了主语she)
她弹奏的钢琴比预料的好得多.
You arrived earlier than necessary.( = than it is necessary for you to arrive )
你比要求的时间到得早.