I、 单项选择 （每题1分，共15分）
（ ）1. Jack is a little ____ than Peter.
A. strong B. stronger C. strongest
（ ）2. Miss Li warns us ____ loud ly in the classroom.
A. not speak B. don’t speak C. not to speak
（ ）3. When you ____ the classroom, please turn off the lights.
A. will leave B. are leaving C. leave
（ ）4. There are many trees on ____ sides of the river.
A. all B. both C. each
