On weekends the Smiths usually drive to the countryside and ________ the fresh air there. [ ]

It is useful book. I borrowed it from school library.

is Tom’s birthday. Let’s have a birthday party tonight,shall we — ____________.

We want someone to design the new art museum forus— ____ the young fellow outside have a try

The theory by Einstein was later to prove true, but at that time few people could accept it.