When people visit Switzerland for the first time，they look with great interest，not only at the mountains but also at a type of clock—a Cuckoo-clock，on sale there．Cuckoo-clocks are very popular with tourists looking for a souvenir．A Cuckoo-clock has a small painted cuckoo that comes out near the top of the clock every half an hour and says，“Cuckoo”．Every hour it comes out and says “Cuckoo” the right number of times．It does not get a sore throat at midnight or mid-day! Children find these clocks wonderful．Adults gradually get annoyed because the cuckoo never misses an hour or a half hour，and this makes a short sleep in an armchair rather difficult．

In Europe，the cuckoo's call is a welcome sign that summer is on the way．This is the time when the mother cuckoo flies round，looking for a nest（巢）to lay one of her eggs．She chooses a nest belonging to another bird which already has eggs．When the nest is left unnoticed for a minute or two，the cuckoo rushes down，lays an egg and hurries off．In this way，she may lay her eggs in as many as four different nests．not one of which has been built by herself．

When a cuckoo egg hatches（孵化），the baby bird is bigger and stronger than the other nestlings．Step by step，it pushes other baby birds and any unhatched eggs out of the nest．In this way，it receives all the food from its foster-parents（养父母）and has a better chance of surviving．

1．When tourists first visit Switzerland，                  ．

A．they are impressed by the mountains

B．they do not find the mountains interesting

C．the Cuckoo-clocks are more interesting to them than the mountains are

D．they find neither the mountains nor the clocks interesting

2．Which of the followings is NOT true?

A．Cuckoos often lay eggs in other birds' nests．

B．If it's exactly 12 o'clock now，the cuckoo will say “cuckoo” twelve times．

C．The cuckoo does not say “cuckoo” at midnight and mid-day．

D．The adults don't like the Cuckoo-clocks as much as the children．

3．Tourists like to buy Cuckoo-clocks                ．

A．to remind them of a visit

B．because they can tell time exactly

C．to amuse their children

D．because they are cheaper than other clocks

4．Why are Europeans happy to hear the call of the cuckoo?

A．They like to catch and eat this large bird．

B．The bird has a beautiful way of singing．

C．This bird is used to tell the time in Switzerland．

D．It makes them think that warmer weather is coming．

5．What may other birds think when a cuckoo lays an egg in their nest?

A．They push it out of their nest．

B．It seems that they don't know what has happened．

C．They don't like it but cannot do anything about it．

D．They welcome the egg and the young cuckoo．