例题：
1. Because of her bike _______, she has to walk to school.
A. was stolen B. being stolen
2. Because her bike _______, she has to walk to school.
A. was stolen B. being stolen
解析：
B。because of为介词，其后的结构不是句子，故不选谓语单词/时态，因为谓语单词/时态即意味着句子。
A。because为引导词，其后的结构为句子，故选择谓语动词/时态的形式。
练习：
1. I can’t do my homework with all this noise _______ on.
A. is going B. going
2. I can’t do my homework when all this noise ______ on.
A. is going B. going
答案：
B，with为介词，其后非句子，不选时态。
A， when为引导词，其后为句子，选时态。
写作：
因为降雨的减少，雾霾天气越来越多。
