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问题 单项选择题

CPU通过接口电路向液晶显示器输出数据时，在接口电路中( )。

A．数据可以直接输出到显示器

B．数据只需经过三态门输出到显示器

C．数据经反相器后输出到显示器

D．数据经锁存后输出到显示器

答案

参考答案：D

解析： 由于显示器在接收CPU送来数据的速爱较慢，故需要在CPU与显示器的接口电路中常加入数据锁存器，以起到速度匹配的作用。

判断题

焦炭中的灰份及硫份均不利于高炉的操作，因此含量愈低愈好。
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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.

58().

A. like

B. as

C. along with

D. up to
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