Answer key 19
1. (While) waiching TV, the boy heard a strange noise coming from the kitchen.
2. Living with her parents, the girl can't stay out very late.
3. If having finished your work，you can help me with mine.
4. Being a law-enforcement officer, he cannot drink on duty.
5. The actor has been in a state of excitement ever since being nominated for the Oscar.
6. After addressing the congregation, the minister left in a hurry.
或 Having addressed the congregation,the minister left in a hurry.
7. It being rather warm,we decided to go for a swim.
8. The students having all left,the teacher started looking over their examination sheets.
9. I know all about corn farming,having grown up in a Southern farm.
10. The door remaining shut,the servant could not hear what was going on inside.
seat是及物动词，本句是we were seated on the sofa的简化。
Returning to the room是简化从句，必须与主要从句同一主语。四个答案中只有B的主语是人，符合这个要求。
空格部分是that are growing today的简化，成为growing today (今天在长的）。若是B，应为that are grown today (今天种下去的）这一句的简化，文法也通，但是如果今天才种下去，不可能“平均年龄50岁”，所以不行。
这是that is earned on loans这个形容词从句的简化。
四个答案都是副词从句简化，条件是要与主要从句同一主语 (the house)，所以只有A或B。the driveway是“车道”，房子不能站在它里面，所以排除掉A，剩下B (When it was seen from的简化)。
After finishing my degree 是 After I finish my degree 的简化，所以主要从句只能用I作主语，因而只有D。
空格以下是who is reading the paper的简化。
A看起来像是when he was drinking the coffee的简化，既然还在喝，不应洗杯子。所以选完成式的B，表示“喝完之后”。
这是 Hainan Island is located to the south...这一句的简化。
这是 while he was working as a porter...的简化。A 中 while he worked a porter当worked的宾语使用，是误把不及物的 work当作及物动词使用。