当你介绍朋友给别人认识,应该说________.A. I'm Mike.B. This is Li Lei.C. He's Li Ming.
— The floor is clean and dry now. Who _______? — Sorry, I don’t know.
Please don’t drop litter _______, you should throw it into the dustbin _______.
Mr Li’s students can call him _______ 57684051 or e-mail him _______ lihua@sina.com.
— Have you _______ read this story before? — Yes. I’ve _______ read it.
The new airport has been in _______ for two years and it _______ to be a quiet place.