--who's the man talking to our teacher--A professor ______ a visit to our school.
A. pays
B. is paying
C. had paid
D. paying
It is certain that ______.
A. an object had exploded three miles above the forest
B. the explosion was not caused by a comet
C. an atomic explosion once happened above the ground
D. some form of life from other planets once visited the earth then
“通过指明一列可执行的运算及运算的次序来描述计算过程”是 (29) 语言的特点。
A. 逻辑式
B. 过程式
C. 函数式
D. 交互式
How to raise the efficiency, ______ is the question.
A. what
B. which
C. that
D. if
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