The children, _____ had played the whole day long, were worn out.
| A．all of what | B．all of them | C．all of whom | D．all of which |
Don’t promise anything ______ you are one hundred percent sure.
| A．whether | B．after | C．how | D．unless |
There were some chairs left over _____ everyone had sat down.
| A．when | B．until | C．that | D．where |
I used to love that film ______ I was a child, but I don’t feel it that way any more.
| A．once | B．when | C．since | D．although |
You’d better not leave the medicine ______ kids can get at it.
| A．even if | B．which | C．where | D．so that |
He found it increasingly difficult to read, ______ his eyesight was beginning to fail.
| A．though | B．for | C．but | D．so |