______ we have all the materials ready, we should begin the new task at once.
A. Since that
B. Since now
C. By now
D. Now that
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If it ______ Professor Russel standing up for him, he would have had to leave.
A. hasn't been for
B. hadn't been for
C. was for
D. were for
Don't forget Ann wants a big doll, ______
A. do you
B. will you
C. don't you
D. won't you
化疗指数是指
A. LD5/ED50
B. ED95/LD5
C. LD50/ED50
D. ED50/LD50
E. LD1/ED99
It is believed that the authorities are thinking of __ new taxes to raise extra revenue.
A. impairing
B. imposing
C. invading
D. integrating
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