-----How many students are there in the classroom?------_______.

— Can you cook eggs with tomatoes ?— Yes, of course. ______ can do it , because it is easy, I think.

 That region has a lot of natural resources while this one has ________.

— Who helped Li Lei with his English?   —         , he learnt it by himself. 

Teaching is ________ everybody can do; it requires patience as well as professional training.