通读下面短文，掌握其大意，然后在各小题所给的四个选项中，选出一个最佳答案，并将其字母编号写在题号前的括号内。
I got an answering machine for my birthday，and I soon got to know 46 a useful machine this is．I 47 outside most of the day，So someone can leave a message and I can 48 back．
There is no way for those who call me to say that they can’t find me．So it will be 49 for them to get in touch with me．Sometimes 50 I am at home and have work to do，the 51 never stops. I like to put the machine on. I am not tired, and I can do 52 work. There are some people I just do not want to 53 . So I put the machine on and I 54 speak to them. It is so useful and helpful that I really do not know how I 55 this wonderful invention.
46．( )A．what B．how C．which D．that
47．( )A．look B．stay C．make D．keep
48．( )A．call him B．call them C．give it D．give them
49．( )A．hard B．simple C．difficult D．easy
50．( )A．what B．where C．when D．why
51．( )A．machine B．radio C．TV D．phone
52．( )A．little B．more C．less D．many
53．( )A．work to B．write to C．send to D．talk to
54．( )A．don't have to B．mustn't C．can't D．won't need
55．( )A．talked B．did C．lived D．played
45．( )While the teacher ________, the students ________ notes.
A．was talking; took B．was talking; were taking
C．talked; took D．talked; were taking
44．( )There are ________ mistakes in his writing that it's hard to correct them all.
A．so much B．so many C．so few D．such many
43．( )The number of the seats in the room ________ about sixty.
A．has been B．are C．is D．be
42．( )-- ________ does Jim listen to the news?
--Every evening.
A．How many B．How long C．How soon D．How often
41．( )--Would you please let me know ________ tomorrow?
--At the school gate.
A．when to meet B．when will meet
C．where to meet D．where will meet
40．( )No one knows the tall boy ________ saved the two girls from the river.
A．whom B．who C．what D．which