单词拼写（每题1分，共8分）

1.It is healthier to keep a b_______ diet every day.

2. The little boy e________ his living by selling newspapers.

3. I’ll come tomorrow,  if the weather p___________

4. Finally, they were able to s_______ shelter from the rain.

5. The first s________ of the play was moving.

6. It’s r_______ to interrupt, so you had better wait.

7. To succeed, we must c___________ talent with hard work.

8. The flower is i________ beautiful, but it produces no fruit.

12个Na₂SO₃恰好与4个K₂Cr₂O₇完全反应，则元素Cr在被还原的产物中的化合价为_____价。