1. Until recently man ... stay underwater for long (couldn't / can't / don't / wouldn't)2. We may know the land very well but we know very ... about the oceans (few / little / least / a little)
3. In a game of singles 2 players play ... each other (with / for / opposing / against)
4. I'm not very fond ... detective stories ( in / of / at / on)
5. ... those electric wires! (Keep away from / Keep off / Stay away / Stay off from)
6. We can learn more about the undersea world ... Jacques Cousteau's invention (on account of / thanks to / because of / due to)
7. With scuba-diving we can take a ... look at marine life (closer / nearer / more careful / more thorough)