He did everything with a full heart. ______, he was always successful.
| A．By the way | B．On one hand | C．As a result | D．At the start |
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 |