一Why are you so tired these days?
一Well,I have work to do.
A:too much
B:too many
C:much too
D:many too
小刚和小红正在讨论一道英语题,小强和另外几个男生在一起议论他俩:“瞧,他俩多'好',他俩有意思……”
已知a→=(2,1)与b→=(1,2),要使|a→+tb→|最小,则实数t的值为____