Your teacher of maths has taught you when to	1.__________
find the centre of a circle! It takes sometime.	2.___________
Here is a simple method.Put the corner of a sheet of paper in	3.___________
the circumference (圆周) of the circle,	4.___________
then make points A and B which the sides of the paper	5.____________
across the circle.You may be sure that points	6.____________
A and B mark the end of a diameter (直径).	7.___________
To draw it, then repeat this process at a	8.__________
different place to get other diameter.	9._______
You will find the centre where two lines cross.	10._________

If you take care notice in some places, you will	(1) ______
see the fact most smokers are young people and even	(2) ______
some are middle school students．It is said that	(3) ______
in China the number of the people smoked is about	(4) ______
45%．Why is so many people smoke? Some	(5) ______
think that smoking is pleasure, some believe that	(6) ______
they can refresh themselves by smoking．In a fact,	(7) ______
smoking is a bad habit, that does great harm to	(8) ______
people' s healthy．The study of smoking shows that	(9) ______
many kinds of disease have nothing to do with smoking．	(10)______

Yesterday we went to plant trees on the hill near to (1)________
our school. The boys were made dig pits（坑）. The	(2)________
girls were told to plant the young trees into the pits.	(3)________
All of us worked very hardly. Soon we were all wet	(4)________
with sweat. After the young trees planted, we	(5)________
began to water it. The water was at the foot of	(6)________
the hill. But we stood in a line to pass pails（桶）	(7)________
of water from one to other up to the hill.	(8)________
We did not finish water the trees until it	(9)________
was dark. Though we were tired, we feel very happy.　　（10）______

When Mary finishes her school, she wants to find a　　 (1)____
good job and has a house of her own in a big city.	(2)____
She hates to make housework when she stays at home,　　 (3)____
and she doesn't want to get marry until she is at least (4)____
Thirty years old. She loves to help other, and right	(5)____
now she intends to get a job in hospital, where she	(6)____
can take care of ill people. In the evenings she plans	(7)____
to go to pictures, plays or parties, but as she does	(8)____
not like to cook, she will eat out in the restaurants.	(9)____
She also likes to take exciting trips to the place she likes.(10)____