下列计算不正确的是（ ）
A.a3÷a5=a-2
B.a3·a-5=a-2
C.（a-3）2=a9
D.（a2）-3=a-6
答案：C
We have learned three ______ words since we came here. [ ]
A. thousand
B. thousands
C. thousands of
D. thousand of
运行中发生过量供给时，应如何处理？
