什么是点火提前角？点火提前角过大和过小有何危害？
题型：问答题 论述题
问题：
什么是点火提前角？点火提前角过大和过小有何危害？
题型：问答题 论述题
Where we live, on the eastern shore of Maryland, the gentle waters run in and out like fingers slimming at the tips.
The Canada geese know this place, as do the white swans and ducks. In the autumn, they come home for the winter. Once or twice each year, snow and frozen rain move into the area. When this happens, if the river is at its narrowest, there is a freeze which hardens the water to the ice.
One morning, a friend of mine set the breakfast table beside the huge window, which overlooked the Tred Avon River. Suddenly she leaned forward and cried out, “There is a goose out
there.”
We saw the figure of a large Canada goose, very iii, its wings folded tight to its sides, its feet frozen to the ice.
Then from the dark sky, she saw a line of swans. They floated from the top of the sky downward and at last landed on the ice. My friend was on her feet now, with one unbelieving hand against her mouth. As the swans surrounded the frozen goose, she feared what life it still had might be pecked（啄）out by those great swan beaks.
Instead, those beaks began to work on the ice. The long necks were lifted and curved down, again and again. It went on for a long time. At last, the goose’s head lifted. Its body pulled. Then the goose was free and standing on the ice. And the swans stood in the air watching. Then, as if it had cried, “I cannot fly,” four of the swans came down around it. Their powerful beaks chipped off the ice and held in the feathers. Slowly, the goose spread its wings as far as they could go, and moved slowly into the sky.
This is a true story. I just think of it in the bad moments, and from it comes only one hopeful question:“ If so for birds, why not for man?”
小题1:What happened to the Canada goose?
A．It was deserted by other geese.
B．It was stuck in the ice.
C．It was wounded and couldn’t fly.
D．It was lost in the water.小题2: At first the author’s friend was worried that ________.
A．the swans would not help the Canada goose
B．the swans would have the same fate with the Canada goose
C．the Canada goose wouldn’t identify with the swans
D．the swans would peck the Canada goose to death小题3:What did the swans do when they saw the Canada goose couldn’t fly?
A．They chipped off the ice held in its feathers.
B．They waited patiently for the ice held in its feathers to melt.
C．They came down and lifted it up to the sky together.
D．They stayed with it and protected it.小题4:What would probably happen to the
author’s friend in the end?
A．She stood there, watching attentively, still feeling a bit worried.
B．She was on her feet, laughing at the swans and the Canada goose.
C．She was embarrassed and went on with her breakfast silently.
D．She stood there quietly, not realizing tears had come down her cheeks.