I used to go camping a lot, so it isn’t the first time I ____in a tent

The world’s elderly population will exceedthat of children by 2060, when each group ________ to account for about one fifth of the population.[ ]

It was several minutes ________ we realized what was happening—our dog was trapped in a newly－dug tunnel.

English is a language ______ in manycountries.

I was about to tell him the secret __someone patted me on the shoulder