科举制选拔官员主要凭靠( )
Grace doesn't like math because she thinks it is ________.
Tom had to______ the invitation to the party last weekend because he was too busy.
K2HPO4
NaCl
H2O
葡萄糖
尿素
酚红
琼脂
0.12g
15mL
0.025g
2.0g
0.25mg
0.5g