用适当的关系代词填空。

1. The man and his paintings ______ we heard of are famous.

2. In the dark street, there wasn't a single person to ______ she could tum for help.

3. Here is the girl ______ schoolbag has been stolen.

4. Mr Johnson said Shenzhen was the first city ______ he had visited in China.

5. The man ______ you talked to a moment ago is Mr. Smith.

6. The girl ______ leg was broken in the earthquake was taken to the hospital.

7. The old man ______ daughter died of SARS is in need of our help.

8. The man and the horse ______ fell into the river were dead.

9. His parents wouldn't let him marry anyone ______ family was poor.

10. Please pass me the book ______ cover is red.

一工厂用软锰矿（含MnO₂约70%及Al₂O₃）和闪锌矿（含ZnS约80%及FeS）共同生产MnO₂和Zn（干电池原料）：

已知① A是MnSO₄、ZnSO₄、Fe₂(SO₄)₃、Al₂(SO₄)₃的混合液。

② IV中的电解反应式为MnSO₄＋ZnSO₄＋2H₂OMnO₂＋ Zn＋2H₂SO₄。

（1）A中属于还原产物的是___________。

（2）MnCO₃、Zn₂(OH)₂CO₃的作用是_____________________________；II需要加热的原因是___________；C的化学式是____________。

（3）该生产中除得到MnO₂和Zn以外，还可得到的副产品是______________。

（4）如果不考虑生产中的损耗，除矿石外，需购买的化工原料是___________。

（5）要从Na₂SO₄溶液中得到芒硝（Na₂SO₄·10H₂O），需进行的操作有蒸发浓缩、________、过滤、洗涤、干燥等。

（6）从生产MnO₂和Zn的角度计算，软锰矿和闪锌矿的质量比大约是__________。