rtgrtghtrfgbfg（）

此题为判断题(对，错)。

An English traveler spent a few weeks in Sweden.When he was about to return home, he found he had only enough money to get a ticket back to England.Thinking the matter over, he decided that as it was only a two-day's voyage he could get home without eating anything.So he bought a ticket with that little money he had and went on board the ship.

He closed his ears to the sound of the lunch bell, and when dinnertime came, he refused to go down to the place where people had their dinner, saying that he did not feel well.

The following day he did not get up until breakfast was over, pretending that he had overslept.At lunch time, too, he kept out of the way.By the time of the dinner, however, he became so hungry that he could even have eaten paper.

“I can't stand this any longer,”he said to himself.“I must have something to eat.” At dinner table he ate everything put in front of him.When he was quite satisfied, he felt stronger and at once went to see the waiter."Bring me the bill," he said to the waiter.

“The bill?” said the waiter in surprise.

“Yes,” answered the traveler.

“There isn't any bill here.” Said the waiter.“On this ship, meals are already included in the ticket.”

31.The traveler thought that he().

A.would find no food served on board

B.could not get home_ without having meals on board

C.could do without any food before he got home

D.would not be allowed to eat on board

32.“He closed his ears to the sound of the lunch bell,” means ()

A.he did not hear the lunch bell

B.he heard the lunch bell but didn't go for lunch

C.he put something in his ears to close them

D.he did not know it was the lunch bell

33.The first day he did not have his lunch because he did not().

A.feel well

B.know the time for lunch

C.hear the lunch bell

D.have the money

34.What did the traveler mean when he said “I can't stand this any longer.”? ()

A.I can't understand it.

B.I can't stay hungry any longer.

C.I can't keep my feet on this place any longer.

D.I must sit down for a while.

35.He became so hungry that he().

A.went to sleep

B.ate paper

C.went to the dinner-table

D.kept out of the way

由一电阻源产生的有效噪声功率为 P=kT W，其中是波尔兹曼常数，T 为热力学温度。请计算在室温时（T=290 K）由电阻产生的有效功率谱密度（每赫兹的功率）。

设,求F(x)+G(x),G(x)-F(x),F(x),G(x).

求f[f(x)],g[g(x)],f[g(x)]与g[f(x)],其中:

设f(x)，g(x)都是可导函数，且|f'(x)|＜g'(x)，证明：当x>a时，