搜题请搜索小程序“爱下问搜题”
问题 单项选择题

（）为薄壁容器。

A.容器壁厚／内径≤1/10

B.容器壁厚／内径≥1/10

C.容器外径／内径>1.2

D.容器外径／内径<1.2

答案

参考答案：A

解析：容器壁厚小于等于容器内径的1／10者为薄壁容器；容器壁厚大于容器内径的1/10者为厚壁容器。

多项选择题

地震灾害事故救援难度大的原因有（）。

A、大地震造成交通、供水、供电、通信等生命线工程毁坏

B、大量人员被埋或失踪，消防、医疗急救等专业救援部门自身遭受不同程度的损害

C、伴随的火灾、水灾和有毒气体泄漏等各种次生灾害往往交织在一起，局势十分复杂

D、救援人员参加地震救援的机会和经验不多，增加了对地震救援的难度

E、救援要求刻不容缓，但力量又一时难以迅速重整和集结
查看答案
单项选择题

For years we have believed we were either healthy or sick. (55) , during the mid-90s, scientists developed a new concept called "sub-health", a status (56) health and illness. The concept of sub-health has become (57) because it has helped to explain many health problems. (58) one study, only 5. 6% of people in the overall population are actually sick, (59) the subhealthy group consists of about 60%, and the (60) population is considered healthy. (61) of one’s sub-health will help one to be alert to the underlying disease and remain healthy. Sub-health is a state in which the body is (62) turning from health to illness or from illness to health. Our bodies are actively (63) the conditions of health, sub-health and disease. Factors (64) aging, internal or external toxicity (毒性), and body or mind exhaustion may cause sub-health, but taking good care of the body can change a sub-healthy status to a healthy one.

57().

A.choosing 

B.comparing 

C.improving 

D.balancing
查看答案