(1)原式=(-112)×12+1
=-1+1
=0;
(2)原式=4-(-2+4)
=4-2
=2.
---You’re trembling. What’s happened?
---- I ______ outside in the cold for over an hour waiting for a bus.
A.was standing
B.have been standing
C.stood
D.will stand
自动调节系统是由()、()、()、()四个主要环节组成。