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【单选题】
焊接30CrMnSiNi2A钢时,除焊后低温回火外,还要采取一定的预热措施,预热温度应 母材淬火后的回火温度。A.
高于
B.
低于
C.
等于
D.
不小于
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【简答题】I have a friend. His name is Jack. ③He is healthy because(因为) he plays sports. He runs every day. He runs to his ___①____ in the morning and he runs ____②____ after school in the afternoon. He can run...
【多选题】下列是T分布的特征的有
A.
以0为中心，左右对称的单峰分布
B.
T分布是一簇曲线，其形态变化与自由度的大小有关
C.
自由度越小，T值越分散，曲线越低平
D.
当自由度趋于 时，T分布即为Z分布
【简答题】听对话，选择正确答案。 1. Who often plays with Mary? A. Jack. B. Mike. C. Lucy. 2. How does Ann often go home? A. By bus. B. By car. C. By bike. 3. What does Tom often do on Sunday? A. Look for things on the Int...
【简答题】What extracurricular activities do you usually have at university? What do you benefit from them?
【单选题】What benefit do sports offer to students’physical health?
A.
Students can keep fit.
B.
Students have a higher self-esteem.
C.
students don’t like smoking.
D.
students learn to relieve stress.
【简答题】( ) 1. My mother often oranges. A eat B.eats C.eating D . eated ( ) 2. My aunt sometimes very well. A. sing B. sings C. singes D . singing ( ) 3. Jack usually grandpa very much. A. miss B. misss C. mi...
【简答题】I like eating fruit and vegetables what are of great benefit to our healthy. Not only do they pr us from falling into ill, but they help us lose weight. I used to hate vegetables, but follow the ...
【单选题】关于t分布的特征,下面描述正确的是( )
A.
t 分布与自由度无关，不受自由度的制约
B.
t 分布密度曲线以t=μ为对称轴，左右对称
C.
t 分布密度曲线是一条非对称曲线
D.
与标准正态分布曲线相比，t分布曲线顶部略低，两尾也稍高而平。
【简答题】Zhang Yang, David, Jack and Mark are new students. It's Sunday today. They 1 go to school. They are 2 at home. David is from America. He is Zhang Yang's 3 . They are in the same 4 . But they are in di...
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