I have two grammars, ______are of great use.
| A．all of which | B．either of which | C．both of that | D．both of which |
How can you expect him to make any progress ________ you never give him a chance to have a try?
| A．when | B．unless |
| C．even though | D．until |
I'm sorry you've been waiting so long，but it'll still be some time ________ Brian
gets back.
| A．before | B．since | C．till | D．after |
His mother likes to have him next to her ________ she can keep an eye on him.
| A．where | B．in which | C．there | D．when |
—You should have thanked the hostess before leaving.
—I meant ________.But I couldn't find her when I was leaving.
| A．to do | B．to | C．doing | D．doing so |
________ change your mind, do let me know.
| A．If should you | B．Should if you |
| C．Should you | D．You should |