_____we are closely united, we can surely overcome these difficulties.
| A．As long as | B．As far as | C．If only | D．As good as |
I looked up and noticed a snake ________ its way up the tree to catch its breakfast.
| A．to wind | B．winding | C．wind | D．wound |
When ________ for his views about his teaching job, Philip said he found it very interesting and rewarding.
| A．asking | B．having asked | C．asked | D．to be asked |
As many as five courses are provided, and you are free to choose ________ suits you best.
| A．whichever | B．whatever | C．whenever | D．wherever |
Interest is as ________ to learning as the ability to understand, even more so.
| A．similar | B．vital | C．available | D．specific |
Everything was placed exactly _______ he wanted it for the graduation ceremony.
| A．though | B．where | C．while | D．when |