A child who lives in an uninteresting environment will develop less intelligence than ______ who lives in a rich and changing environment.

Whoever does not have a mobile phone must borrow _____ because you will certainly need ____ for the tour.

----- Which is your favorite sport, swimming, running or skating?------_______ of them. I like water skiing best.

 –How many students are there in the classroom? --__________. They are all in the lab.

. She learnt both business and history, but she knows________of them well, though she can speak on subjects in general.