Recently some studies have found that learning ____________ second language can lead to _______________ increase in one’s brain power.
| A．a; the | B．不填; the | C．a; an | D．the; an |
She told me that her father______to the post office when I arrived.
| A．just went | B．has just gone |
| C．had just gone | D．had just been going |
By the time he was ten,Edison______experiments in chemistry.
| A．had already done | B．already had done |
| C．was already doing | D．already did |
______,the boy couldn’t enter his house.
| A．Since the key had lost | B．T he key being lost |
| C．Lost the key | D．Having lost the key |
Be quick,or you’ll get______in the rain.
| A．to be caught | B．catching | C．to catch | D．caught |
He insisted______the working site.
| A．to be sent to | B．being sent to |
| C．on being sent to | D．that to be sent to |