英語の正誤問題について

質問

英語の正誤問題についてです。もし間違っている場合は何がどう変わるのか教えていただきたいです。
1． Seeing the beautiful girlsmile, you'll feel happy.
2. I don't know how to do about this situation.
3. My father makes a rule to take a walk before breakfast.
4. The car salesman tempted me to buy a new model.
5. Everybody believes Tom to an honest man.
6. You should find a house to live before you get married.
7. This box is so heavy for me to lift, so I need your help.
8. This lake is dangerous to swim.
9. I ran fast enough to get to the station in 5 minutes.

自分でも答えだしてみましたが自信ないです・・・
1．○
2．×　how→what
3. ×　makes a rule→makes it a rule
4. ○
5. × to an honest →to be an honest
6. ○
7. ×　so heavy→too heavy
8. ×　to swim→to swim in
9. ○

回答No.1

sayshe

6. You should find a house to live [in] before you get married.
結婚する前に、住む家を見つける方がいいですよ。

以外、私も質問者さんと同じ答えになりました。