3- 在下列各组酸碱物质中,属于共轭酸碱对的是( )? a. H 3 PO 4 -Na 2 HPO 4 b. H 2 SO 4 -SO 4 2- c. H 2 CO 3 -CO 3 2- d. NH 3 +CH 2 COOH-NH 2 CH 2 COO - e. H 2 Ac + -Ac - f. (CH 2 ) 6 N 4 H + -(CH 2 ) 6 N 4
【简答题】根据句子意思,用所给单词的正确形式填空。 1. ________ is very important. (healthy) 2. The ________ month of a year is February. (two) 3. We must clean our hands before ________ meals. (have) 4. He asked ________ to write ...