I've become good friends with several of the students in my school _______ I met in the English speech competition last year.
A:who
B:where
C:when
D:which
该反应所属的基本反应类型为____,上述物质中,属于单质的有____(填化学式)。
若函数f(x)唯一的零点在区间(1,3)、(1,4)、(1,5)内,那么下列命题中错误的是( )