Please help me correct my English sentence errors, urgent! If you answer well, you will be rewarded

1.Write the phone number down in case you should forget it. (The in case clause uses the virtual should verb prototype)

2. It dawned on me that I had left my purse at home when I was about to pay my phone bill. (Forgot happened before was about to pay so use past perfect tense)

3. While I was in London, I went to the British Museum several times. (The preposition during cannot introduce a clause, so it is changed to the subordinating conjunction while)

4. Times have changed, and we should change, too. (times is era)

5. I thought I heard someone come in while I was surfing the Internet.

6. He sent me a text message to remind me that the composition was due the next day.

7. The world is changing so fast that we can hardly keep up with the pace of change.(so,,that so,,that)

8. My yesterday's supper consisted of whole wheat noodles, cabbages and chicken . (cabbage is a countable noun and must be pluralized)

9. The farmer said that he had four children to take care of. (take care of is a fixed phrase)

10. This is an area which the United States regards as its backyard. (The antecedent of the attributive clause cannot be repeated in the clause, so there is no pronoun it)