-2的相反数是( )
A:2
B:-2
C:12
D:-12
冰箱里的食物不容易腐烂变质,你认为是什么因素限制了冰箱里细菌和真菌的繁殖()
We all know that we’ll meet all kinds of difficulties in our lives in the future. We should learn to be ________ any challenge!