1.make为使役动词,故后面的动词用原形.make sb do sth
故正确答案：the bad news made us feel very sad（LZ少了made的宾语）
2.昂贵的expensive
3.decide to do sth
故正确答案：we decide to go on vacation in Beijing
4.and前后时态一致,故前句也应该用过去时态.
故正确答案：he stayed at home and did his homework
5.前面说了是今天很热,那后面肯定说的就是今天是哪一天呢?是夏天的第一天.
故正确答案：the weather is nice today.it's the first day of the summer