实验室里不同化学试剂的保存方法不尽相同,①NaOH溶液 ②大理石 ③NaCl溶液④稀硝酸4种试剂通常各自存放在下列图示的某种试剂瓶中。按照试剂瓶的顺序存放试剂序()号正确的是
A:①②③④
B:②①④③
C:②③④①
D:②①③④
I will take a holiday with my family _______ I finish all the exams.
—Miss Gao has ____________ free time than Mr Green.—I think so. She is busy every day.
-2的相反数的倒数是( )