—Have you been wasting time chatting online recently?
—________. I've been studying hard and I need a break.
| A．Not really | B．Don't mention it |
| C．Not to worry | D．Never mind |
The fact has worried the people across the world ___________ the earth is becoming warmer and warmer these years.
| A．what | B．which | C．that | D．where |
Bob would have helped us yesterday, but he ____________.
| A．is busy | B．had been busy | C．has been busy | D．was busy |
The girl arranged to have piano lessons at the training center with her sister ________ she would stay for an hour.
| A．where | B．who | C．which | D．what |
I have told you the truth. ________ I keep repeating it?
| A．Must | B．Can | C．May | D．Will |
Because of the Mid-autumn Day happening to come along, we have just enjoyed a longer National Day vacation than ever before, but it is estimated that it will be 38 years ___________ we can experience such a coincidence again.
| A．that | B．before | C．since | D．when |