核素显像准直器的选择主要考虑的因素中下列哪一点是错误的（）
A.需要考虑显像剂发射的主要γ射线能量
B.需要考虑所用放射性活度
C.需要考虑显像目的
D.需要考虑对灵敏度及分辨率的要求
E.如131I和123I常选用高能型准直器，99mTc则选用低能型准直器
参考答案：E
解析：如99mTc和123I常选用低能型准直器，131I则选用高能型准直器。
完形填空 阅读短文，从每题所给选项中选出可以填入空白处的最佳选项（共15分；每空1分，满分15分） When I was young，my father told me that little acts of kindness may give one great happiness. Since then I have always tried to help people in . One hot summer afternoon, I was down the highway to New York when another car suddenly into my lane(车道). My car was in the far right lane，so it ran onto the roadside. As a(n) driver，I moved my car quickly and skillfully back onto the highway without causing any accident. I was with that driver，but I thought that he just did not pay attention to（注意） the lane change, and he did not do that on purpose(故意).The car ran away after cutting me off. Very soon it disappeared from sight. After a while，I came around a curve(弯道) and found the car. The driver was walking along the roadside. He was an elderly man and looked . As there was no telephone nearby and the nearest services were twenty miles away, I decided to and see what the problem was. The man’s car had a flat tire(瘪胎). Although he had another tire，he had nothing to work with. I decided to him. I changed the tire for him and allowed him to sit in my air-conditioned car while I did it. Fifteen minutes later，I the work. I was hot and tired，but I really felt after an act of kindness to the man who had earlier my car run off the road. You can really enjoy great from kindness acts, so always lend your hands to others in trouble.
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(由单选和多选组成)
| 某年世界非产油发展中国家的债务余额为15428亿美元，其中当年应偿还本金和应付债务利息为2315.7亿美元。而当年非产油发展中国家商品和劳务出口收入为8541.3亿美元。当年非产油发展中国家的国民生产总值为12575亿美元。 根据以上材料，回答下列问题： |
根据国际公认的负债率参考数值来看，该年非产油发展中国家的债务负担( )。
A．适度
B．较轻
C．较重
D．无法判断