读“地球光照示意图”，完成下题。
下图为DNA分子部分结构示意图，以下叙述正确的是（）
阅读下面的短文，从所给的单词中选择合适的单词补全短文，每空只填一词，每词只准用一次，注意书写工整。
fly, flying, buy, take, taking, stay, bought, with, was, favourite, bored, fever
Sam ____ very sad last weekend. He was ill. He had a ____. His mother asked him to ____ in bed. He was very ____. Saturday afternoon, his good friends Tom and Mike came to see him. They ____a lot of fruit and some flowers for Sam. He was very happy.
This weekend, Sam is going to go hiking ____ his friends. They are going to fly kites, ____ pictures and play football. Because Sam likes____ kites. Tom's hobby is ____ pictures. And playing football is Mike's____ sport.
把肯定句改成双重否定句
①这是活泼机灵的小燕子。
②他必须这么做。
