单句改错

1. I had some trouble to finding Tom's house.

2. When did your father join in the party?

3. How are you getting on well with your classmates recently?

4. Mr Smith said that he would leave for Shanghai next Monday.

5. The speech that he made concerned the project upset me.

6. While Tom walking the dog in a street,he met an old friend.

很少有热塑性的水溶性聚合物用于涂料，是因为（）。

A、它的抗水性太差

B、毒性较强

C、原材料费贵

D、成膜难