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【单选题】
使用内部程序存储器时,51单片机的EA引脚( )。
A.
必须接地
B.
必须接+5V电源
C.
可悬空
D.
以上三种情况视需要而定
拍照语音搜题，微信中搜索"皮皮学"使用
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【单选题】The amount of time a person sits during the day is associated with a higher risk of heart disease, diabetes, cancer, and death, regardless of regular exercise, according to a recent study. More than o...
A.
Regular exercise will help counteract the negative effects of being sedentary.
B.
Physical activity alone may not be enough to reduce the risk for disease.
C.
Sitting still causes some types of heart disease and cancer.
D.
Watching television while on a treadmill is considered sedentary time.
查看完整题目与答案
【单选题】听力原文：W: I must have told Mike five times not to forget the meeting. And he still missed it. M: Well, you know Mike everything's in one ear and out the other. Q: What can be inferred about Mike? (16)
A.
Mike doesn't always listen.
B.
Mike's never missed a meeting.
C.
Mike had to attend another meeting.
D.
Mike has an ear infection.
查看完整题目与答案
【单选题】高龄老年人是指老年人的年龄
A.
≥60岁
B.
≥65岁
C.
≥70岁
D.
≥75岁
E.
≥80岁
查看完整题目与答案
【简答题】硫酸亚锡（SuSO 4 ）是一种重要的硫酸盐，广泛应用于镀锡工业。某研究小组设计SnSO 4 制备路线如下： 查阅资料： I．酸性条件下，锡在水溶液中有Sn 2+ 、Sn 4+ 两种主要存在形式，Sn 2+ 易被氧化。 II．SnC1 2 易水解生成碱式氯化亚锡[Sn(OH)Cl]。 回答下列问题： （1）SnC1 2 粉末需要加浓盐酸进行溶解，请用化学方程式说明原因_______________...
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【判断题】Improving your study habits means having better learning techniques
A.
正确
B.
错误
查看完整题目与答案
【单选题】测段改正后高差为( )。
A.
该段实测高差+该段高差改正数
B.
该段实测高差-该段高差改正数
C.
该段实测高差闭合差+该段高差改正数
D.
该段实测高差闭合差-该段高差改正数
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【单选题】一 I still cannot figure out why he missed his flight . 一 He an accident on the way to the airport .
A.
could have had
B.
should have had
C.
would have had
D.
must have had
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【单选题】Which of the following sentences does NOT express a presumption?
A.
Why isn't he here? He must have missed the train.
B.
Bad seeds must bring bad crops.
C.
He can't have been to your home. He doesn't know your address.
D.
You must be Mr Jones.
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【多选题】平面上的等高线的说法正确的是:
A.
一定是直线
B.
在标高投影图中一定互相平行
C.
可能是曲线
D.
高差相等时，等高线间距也相等
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【单选题】You've made some progress in your study.But it still remains ().
A.
improving
B.
improvement
C.
to improve
D.
to be improved
查看完整题目与答案
相关题目：
【单选题】The amount of time a person sits during the day is associated with a higher risk of heart disease, diabetes, cancer, and death, regardless of regular exercise, according to a recent study. More than o...
A.
Regular exercise will help counteract the negative effects of being sedentary.
B.
Physical activity alone may not be enough to reduce the risk for disease.
C.
Sitting still causes some types of heart disease and cancer.
D.
Watching television while on a treadmill is considered sedentary time.
查看完整题目与答案
【单选题】听力原文：W: I must have told Mike five times not to forget the meeting. And he still missed it. M: Well, you know Mike everything's in one ear and out the other. Q: What can be inferred about Mike? (16)
A.
Mike doesn't always listen.
B.
Mike's never missed a meeting.
C.
Mike had to attend another meeting.
D.
Mike has an ear infection.
查看完整题目与答案
【单选题】高龄老年人是指老年人的年龄
A.
≥60岁
B.
≥65岁
C.
≥70岁
D.
≥75岁
E.
≥80岁
查看完整题目与答案
【简答题】硫酸亚锡（SuSO 4 ）是一种重要的硫酸盐，广泛应用于镀锡工业。某研究小组设计SnSO 4 制备路线如下： 查阅资料： I．酸性条件下，锡在水溶液中有Sn 2+ 、Sn 4+ 两种主要存在形式，Sn 2+ 易被氧化。 II．SnC1 2 易水解生成碱式氯化亚锡[Sn(OH)Cl]。 回答下列问题： （1）SnC1 2 粉末需要加浓盐酸进行溶解，请用化学方程式说明原因_______________...
查看完整题目与答案
【判断题】Improving your study habits means having better learning techniques
A.
正确
B.
错误
查看完整题目与答案
【单选题】测段改正后高差为( )。
A.
该段实测高差+该段高差改正数
B.
该段实测高差-该段高差改正数
C.
该段实测高差闭合差+该段高差改正数
D.
该段实测高差闭合差-该段高差改正数
查看完整题目与答案
【单选题】一 I still cannot figure out why he missed his flight . 一 He an accident on the way to the airport .
A.
could have had
B.
should have had
C.
would have had
D.
must have had
查看完整题目与答案
【单选题】Which of the following sentences does NOT express a presumption?
A.
Why isn't he here? He must have missed the train.
B.
Bad seeds must bring bad crops.
C.
He can't have been to your home. He doesn't know your address.
D.
You must be Mr Jones.
查看完整题目与答案
【多选题】平面上的等高线的说法正确的是:
A.
一定是直线
B.
在标高投影图中一定互相平行
C.
可能是曲线
D.
高差相等时，等高线间距也相等
查看完整题目与答案
【单选题】You've made some progress in your study.But it still remains ().
A.
improving
B.
improvement
C.
to improve
D.
to be improved
查看完整题目与答案