President Obama won the 2012 election over Romney and is once more in__ of the White House.
| A．return | B．search | C．relief | D．power |
It is announced that big prizes will go to ________ finishes the assignment on time.
| A．whom | B．who |
| C．whomever | D．whoever |
The pupils were playing games in the classroom ________ a gunman entered and began shooting wildly at them.
| A．while | B．when |
| C．as | D．before |
Actually, the London Olympic Park is built ________ there used to be a poor area called East London.
| A．what | B．when |
| C．where | D．why |
You had better book rooms at the hotel in advance ________ you should find no room on your arrival.
| A．so that | B．even if |
| C．in case | D．now that |
________ you are unable to deal with it, perhaps we should ask someone else for help.
| A．Although | B．While |
| C．Since | D．Unless |