什么是酶分子的化学修饰？有何作用？

After six months’ busy work, Tom wants to take a vacation. He thought about going to America, but decided      Majorca, an island (岛) in Spain. Every      Tom goes for vacation, he just stays in the hotel all day and night. The      thing he does is visiting the club. It’s still within (在……之内) the     . It’s not      at all. This time Jack, Tom’s friend, told him that Majorca is a beautiful place, and he could have lots of things to do and have a lot of  . He also     , “There are very interesting parks,      you can have a great time. There are many exciting sports too, such as climbing the mountains and     . They can bring happiness to you. You’ll      all your problems.”
Tom is glad to hear that. He is sure that he is having a great vacation.

小题1:	A．to B．for C．on D．in

小题2:	A．week B．month C．day D．time

小题3:	A．only B．different C．busy D．same

小题4:	A．island B．city C．hotel D．trip

小题5:	A．cheap B．interesting C．beautiful D．boring

小题6:	A．money B．fun C．work D．illness

小题7:	A．thought B．heard C．planned D．said

小题8:	A．so B．but C．because D．if

小题9:	A．going riding B．going sleeping C．renting videos D．watching TV

小题10:

A．remember B．take C．forget D．make