问题补充：
When my mom saw the gift I had prepared for her, she .
A. pleased, burst into laughter
B. pleasant, burst into laughter
C. pleasant, burst out laughing
D. pleased, burst out laughing
答案：
A. pleased, burst into laughter
(答案→)B. pleasant, burst into laughter
C. pleasant, burst out laughing
D. pleased, burst out laughing
解析：pleased 高兴的，修饰人，pleasant 令人高兴的，修饰物，短语：burst into laughter 突然大笑起来，句意：当我的母亲看到我为她准备的令人高兴的礼物时，她突然大笑起来。所以选B。
