对于繁殖后代而言，花中最重要的结构是

A．花瓣和花托

B．雌蕊和雄蕊

C．花托和花丝

D．花瓣和萼片

1. The rain is not falling so         ( heavy) now.

2. We used to        (express) our feeling by the letter.

3. I'm used to         ( brush) my teeth at noon and in the evening.

4. He said it         ( serious) without even smiling.

5. These activities are very meaningful. They are good for the mental       ( develop)  of the students.

6. Last holiday the little girl enjoyed         ( her)  in the party.

7. It gets dark, but they are still waiting        ( patient) .