- Do you like the green one or the yellow one?
- I have no idea. I can't decide __________.
A:to choose which one
B:which one should I choose
C:I should choose which one
D:which one to choose
H+____; OH﹣____; CO32﹣____; Cl﹣____; SO42﹣____;NH4+____.
元朝时期建立的并对后世影响深远的制度是( )