寿命周期成本包括( )。
A.研制费用
B.生产费用
C.使用费用
D.以上皆是
参考答案:D
化简:
(1)6a-4a;
(2)(-2ab+3a)-2(2a-b)+2ab.
-----Hello! ______ Lisa speaking. Is that Linda speaking?
----Sorry, she is not at home.
A.This is
B.I’m
C.That is
D.She is