根据短文内容，选择正确答案。
Thomas is an office clerk. Every day he is busy with his work. After a day's work he is often very tired. His wife, Katherine, has no job, so she stays at home to cook the meals. Every day he can have his dinner when he gets home from office.
One day, Thomas came home very late because he was very busy with an important paper. He was very hungry when he got home. When he found dinner was not ready he was very angry with his wife. He shouted at her, “I'm going to have dinner in a restaurant.” “Wait for five minutes,” said his wife. “Why? Do you think that dinner will be ready in five minutes?” asked Thomas.
"Of course not,” she answered. “But I can be ready to go with you in five minutes.”
H+ + CH3COO-已达平衡，若要使醋酸的电离程度和溶液的pH都减小，应加入的试剂是（ ）
