_____twice, the postman refused to deliver our letters unless we chained our dog.
| A．Being bitten | B．Bitten | C．Having bitten | D．To be bitten |
_____has happened many times, children may get drowned in this river.
| A．As | B．Which | C．What | D．That |
There is a mountain_____the top is always covered with snow.
| A．whos | B．of which | C．its | D．that |
The reason_____the manager explained at the meeting sounds reasonable.
| A．which | B．what | C．why | D．for which |
I like to go shopping at the weekdays,_____the shop isn’t crowded.
| A．which | B．when | C．that | D．where |
The Science Museum,_____we visited during a recent trip to Britain, is one of London’s touristattractions.
| A．which | B．what | C．that | D．where |