How can you expect him to make any improvement ________you never give him an opportunity to have a try?
| A．unless | B．when | C．until | D．while |
David is ___ animal fur ,so he won’t visit anyone who has cats or dogs in the house .
| A．curious about | B．allergic to |
| C．satisfied with | D．fond of |
while intelligent people can often ____ the complex ,a fool is more likely to complicate the simple .
| A．sacrifice | B．substitute |
| C．simplify | D．survive |
They _____ on the program for almost one week before I joined them and now we ____ on it as no good results have come out so far.
| A．had been working ;are still working |
| B．had worked ;were still working |
| C．have been working ;have worked |
| D．have worked ;are still working |
____ how others react to the book you have just read creates an added pleasure.
| A．Hearing | B．Hear |
| C．Having heard | D．To be hearing |
The driver was at ____ loss when ______ word came that he was forbidden to drive for speeding.
| A．a; the | B．; / |
| C．the ; the | D．a ; / |