(a-b)^2+4ab/a+b -a^2b-b^2a/ab Giúp mik vs

a. Cấu trúc để viết câu lại câu qua lại này là gì ạ?

1. How long have you bought this car ?

-->When did you buy this car?

2. When did you start to listen to classical music ?

-->How long have you started to listen to classical music?

b. Giải giúp em câu này

We ( phone) .........you as soon as we ( arrive)....................in Ha Noi.

Choose the best answer.

We are looking for ____ place to spend ____ night.

Choose the best answer.

Please turn off ___ lights when you leave ___ room.

Choose the best answer.

I like _____ colorful costumes of ____ ethnic minority people in Vietnam.