English is difficult________. Nobody can learn to use it in a few minutes.
| A．learning | B．to be learned | C．learned | D．to learn |
My parents would have come to see you if it had been possible, but they ________ so busy.
| A．were | B．had been | C．have been | D．would be |
Mary is a(n) _______ customer, so the waiter knows her likes and dislikes.
| A．usual | B．ordinary | C．common | D．regular |
Recently I bought a ticket for Shanghai World Expo, _______ was very reasonable.
| A．the price of it | B．whose price | C．the price of whose | D．the price |
—I’d like to call you at 10 o’clock next Friday morning if it is convenient.
—I’m afraid I _______ an important meeting.
| A．will have attended | B．will be attending | C．will attend | D．would attend |
What some teenagers don’t realize is ____ difficult life can be if they get addicted to drugs.
| A．how | B．what | C．that | D．why |