“a=2”是“直线ax+2y=0平行于直线x+y=1”的 [ ]
A.充分而不必要条件
B.必要而不充分条件
C.充分必要条件
D.既不充分也不必要条件
答案:C
Mr. Zhang, our math teacher, is strict with students and serious in teaching work, so he ____.
A.thinks highly of
B.is thought highly
C.is highly thinking
D.is highly thought of
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