________ is often the case with children，Amy was better by the time the doctor arrived.
| A．It | B．That | C．What | D．As |
Peter was so excited _________ he received an invitation from his friend to visit Chongqing.
| A．where | B．that | C．why | D．when |
The international agreement, __________to help people kick off the habit of smoking, was signed two years ago.
| A．intended | B．intending | C．intends | D．to intend |
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 |