语法与词汇
Required by law to register by the end of the year,the post office was crowded with legal aliens attemptingto comply with the law before the deadline.
【正确答案】Required by law to register by the end of the year, legal aliens crowded into the post office, attempting to comply with the law before the deadline.
【答案解析】Required的逻辑主语应该是legal aliens而不是the post office。