_____several times，but unfortunately，the boy still couldn’t smooth away the problem on his own.
| A．Having been explained | B．The problem having been explained |
| C．The problem had been explained | D．Although the problem had been explained |
More than one-third of the Chinese in the United States live in California, _____ in San Francisco.
A. previously B. predominantly C practically D. permanently
---You are devoted herself_____ to her research and it earned her a good reputation in her field.
| A．strongly | B．extremely | C．entirely | D．freely |
She’s asked me_______ to build the church.
| A．how long it was taken | B．how long it had taken |
| C．how much time did it take | D．how much time it was taken |
No one has _____ been able to trace the author of the poem.
| A．still | B．yet | C．already | D．just |
The ship was _____ in a storm off Jamaica.
| A．drowned | B．sunk | C．wrecked | D．submitted |