在揭开汽轮汽缸大盖时必须遵守哪些事项？

Do you know Australia? Australia is the largest island in the world. It is a little smaller than China. It is in the south of the earth.  1 The population of Australia is nearly as large as that of Shanghai.  2 The cities in Australia have got little air or water pollution. The sky is blue and the water is clean. You can
clearly see fish swimming in the rivers. Plants grow very well.
Last month we visited Perth, the biggest city in western Australia, and went to a wild flowers’ exhibition  3 We had a wonderful time. Perth is famous for its beautiful wild flowers. In spring every year Perth has the wild flowers’ exhibition.
After visiting Perth, we spent the day in the countryside. We sat down and had a rest near a path at the foot of a hill. It was quiet and we enjoyed ourselves. Suddenly we heard bells ringing at the top of the hill. 4  There were about three hundred sheep coming towards us down the path.  5  After a short drive from any town, you will find yourself in the middle of white sheep. Sheep, sheep, everywhere are sheep.

A．The government has made enough laws to fight pollution.
B．Australia is the sixth largest country in the world.	C．Australia is famous for its sheep and kangaroos.
D．Australia is big, but its population is not large.

E. What we saw made us pick up all our things and run back to the car as quickly as we could.
F. There we saw a large number of wild flowers we had never seen before.
G. The people of Australia are very hardworking.