A:discovered
B:would have discovered
C:will discover
D:discover
①100mL 0.1mol•L﹣1H2SO4溶液 ②100mL 0.15mol•L﹣1 HCl溶液
③100mL 0.2mol•L﹣1 CH3COOH溶液 ④200mL 0.1mol•L﹣1 CH3COOH溶液
It's ____ (windy/ rainy) in Beijing.