A:3
B:4
C:5
D:6
只用一种试剂就可一次性鉴别稀硫酸、氢氧化钾溶液、氯化钙溶液的是( )
_______the exam, we'll say good-bye to our dear teachers, classmates as well as ourbeautiful school.
已知函数fx是R上的偶函数,当x≥0时fx=x-1,则fx<0的解集是( )