题目

下列说法中，正确的是(   )A.水是由一个氧元素和两个氢元素组成的B.水是由氧和氢两种元素组成的C.水是由氧和氢两种单质组成的D.水分子是由氧分子和氢分子构成的  答案：B解析:略 Peter: Hi, Sally. Come and have a look at my photos.Sally: Are these the photos you took in Africa, Peter?Peter:   小题1:   Look, this is a wildebeest. It’s an animal in Africa.Sally:   小题2:    Peter: No, it doesn’t. It only eats grass.Sally: Are there a lot of animals in Africa?Peter:   小题3:  Sally: Oh, this photo looks interesting. What are you doing there?Peter:   小题4:  Sally: Did you have a good time there?Peter: Of course.   小题5: