A:will play
B:have played
C:played
D:play
某同学鉴别NH4HCO3、NH4Cl、KCl三种化肥的过程如图,其中,试剂甲和乙分别是( )
— How can I get information ________ space travel?
— You can go online to search ________ information.
关于经线和纬线的叙述正确的是( )