把下列句子改为宾语从句
1.How can we get to the airport?
I don’t know （ ）.
2.Where did you find the book?
Could you tell me（
3.Who has left for Haikou?
Nobody knows（ ）.
4.Can he speak English?
I want to know（ ）.
5.Will they go to the park on foot?
DO you know（
6.Does he work in China?
I am not sure（ ）.
7.What are they looking for?
Do you know（
8.How can they go there?
I didn’t know（ ）.