今天有7节课，上午上好4节课，下午还要上几节课？

任务型阅读 
    My friend, Tom lives a happy life.（1）He usually gets up at 6:00 . Then he goes for a walk. At 7:00 he comes back. He brushes his teeth and takes a shower. （2） Then he eats breakfast. After breakfast, he goes shopping（购物）with his friends. （3）他大约十点半到家。And he cooks lunch. After lunch, he goes to the club. He reads books and plays chess. He eats dinner at home at 6:00 pm. （4）           the evening he likes watching TV. At around 9:00 pm he goes to bed.
根据短文内容，完成下列任务

已知集合A={x|x（x﹣1）=0}，那么（   ）

甲基绿使DNA呈现绿色，吡罗红使RNA呈现红色．利用含有这两种物质的混合染色剂对真核细胞进行染色，显微观察可以发现（    ）

钼是稀有矿产资源，主要用于航天合金材料制作．在元素周期表中钼元素的某些信息如图所示，下列有关钼的说法正确的是（   ）