Text 2 A very important world problem — in fact, I think it may be the most important of all the great world problems which face us at the present time — is the rapidly increasing pressure of population on the land. The population of the world today is about 4,000,000,000. That is an enormous number, yet it is known quite accurately, because there are very few parts of the world which have not carried out a modem census. The important thing is not so much the actual population of twenty million — about six months’ increase in world population. Take Australia for example, there are ten million people in Australia. So it takes the world about three months to add to itself a population which peoples that vast country. Let us take our own crowded country, England and Wales — forty-five to fifty million people. This is just about a year’s supply. By this time tomorrow, and every day, there will be added to the earth about 120,000 extra people — just about the population of the city of York. I am not talking about birth rate. This is net increase. To give you some idea of birth rate, look at the second hand of your watch. Every second, three babies are born somewhere in the world. Another baby! Another baby! You cannot speak quickly enough to keep up with the birth rate. This enormous increase of population will create immense problems. By AD2000, unless something terrible happens, there will be as many as 7,000,000,000 people on the surface of the Earth! So this is a problem which you are going to see in your lifetime. According to the author, Australia ______.
A. has a population of twenty million
B. is a vast country that needs a bigger population
C. constitutes one-fourth of the world’s population increase every year
D. has a population that happens to be one-fourth of the yearly world increase
You will hear a talk. As you listen, you must answer questions 21—30 by writing NO MORE THAN THREE words in the space provided on the right. You will hear the talk TWICE. Where did some Mayans go after they left the central area
第二度Ⅱ型房室传导阻滞
A. P-R间期<0.20S
B. P-R间期>0.20S
C. P-R间期逐渐延长
D. P-R间期固定不变
E. P-R间期固定不变,但可以延长或正常范围内
Text 2 A very important world problem — in fact, I think it may be the most important of all the great world problems which face us at the present time — is the rapidly increasing pressure of population on the land. The population of the world today is about 4,000,000,000. That is an enormous number, yet it is known quite accurately, because there are very few parts of the world which have not carried out a modem census. The important thing is not so much the actual population of twenty million — about six months’ increase in world population. Take Australia for example, there are ten million people in Australia. So it takes the world about three months to add to itself a population which peoples that vast country. Let us take our own crowded country, England and Wales — forty-five to fifty million people. This is just about a year’s supply. By this time tomorrow, and every day, there will be added to the earth about 120,000 extra people — just about the population of the city of York. I am not talking about birth rate. This is net increase. To give you some idea of birth rate, look at the second hand of your watch. Every second, three babies are born somewhere in the world. Another baby! Another baby! You cannot speak quickly enough to keep up with the birth rate. This enormous increase of population will create immense problems. By AD2000, unless something terrible happens, there will be as many as 7,000,000,000 people on the surface of the Earth! So this is a problem which you are going to see in your lifetime. The present net increase of world population is ______.
A. 180 per minute
B. one per second
C. 120,000 per week
D. too many to be counted