The ___________ of surfing the Internet is how you can tell whether the information is true or not．

A．ability        B．competition   C．challenge      D．knowledge

A good teacher always leaves his students enough time to think and voice their opinions in class，_________ sometimes he may not complete his teaching task．

A．even if        B．in case       C．as long as      D．as if

Snowing hard outside， ________ ?

A．doesn't it    B．isn't it        C．does it        D．is it

I spent _____________ seemed to be a short period of time learning maths, but I did get somewhere．

A．which      B．that           C．it            D．what

―I'm afraid I can't get on well in tomorrow's interview．

― ___________ You've prepared for it for quite a few days and surely you will make it．

A．Good luck   B．Cheer up       C．Don't mention it   D．Never mind

―Will $200 __________ the cost of the damage of your car?

―I'm afraid not．I need at least $100 more．

A．do         B．include         C．afford        D．cover

―You see，I'm poor in maths，you are not good at English，and…

―That's _____________ we should help each other．

A．when       B．where         C．how          D．what

―What does the sign over there read?

―No person ___________ smoke or carry a lighted cigarette in this area．

A．will         B．shall          C．may          D．must

Obama，the first black president in American history，________ presidency on January 20th，2009．

A．set up       B．held up        C．took up       D．picked up

Now many companies across the globe are ____________  their employees because of the serious financial crisis．

A．laying off     B．paying off      C．laying out     D．setting aside