实验课上，赵老师指着一平敞口放置的氢氧化钠溶液说它变质了．同学们对其中的溶质做了猜想．

根据句意，用所给动词的适当形式填空。
（1）To keep safe, everyone____  (tell) to wear a seat belt in the car now.
（2）If we cut down the trees, floods____ (wash) our village away.
（3）The microphone is used to____  (make) your voice sound louder.
（4）All the team members were seen____  (train) hard when I passed the room.
（5）Mr. Dong ____  (live) here since he was born.

某高三同学复习时将巴尔扎克的《人间喜剧》、高尔基的《母亲》、列宾的《伏尔加河上的纤夫》放到一起寻找主题。你认为比较合适的一项是（    ）