Read the following passage. Complete the diagram by using the information for the passage. Write NO MORE THAN 3 WORDS for each answer.
Since it was founded a year ago, the babysitting pool has become increasingly popular in the United States. More and more mothers have joined it and have benefited from it. What attracts them most is the idea that you pay your babysitter not in cash, but in paper cards. When you join the babysitting pool, you are given thirty cards, which are worth 30-minute babysitting time each. For each half an hour while you are gone, the babysitter gets paid one card.
There are rules regulating this service. You should not watch more than three kids at a time including your own. On big holidays, such as Christmas and Thanksgiving, the babysitter should be paid twice as much, which means two cards for every half an hour. When you leave the babysitting pool, you should return all the cards. If you are out of cards, you cannot use money instead. You should have to baby-sit for others to earn enough cards so that you will have them handy when you yourself need a babysitter.
Many mothers think highly of this service. It keeps children in constant touch with one another, and makes life easier for the mothers. Since in most cases, the babysitter is the mother who watches other kids at her own home, it is still possible for her to do her own things while the kids play with each other. In fact most mother babysitters find that their own kids are less of a monster and easier to watch when they are around other playmates. Moreover, since the babysitting pool service does not involve money, it will not be a financial loss to the family.
In the past year, the babysitting pool has helped so many mothers with their work that they all think that it is indeed a good community service worth keeping.
H++OH-，在不同温度下其平衡常数为Kw(25 ℃)=1．0×10-14，Kw(35 ℃)=2．1×10-14。则下列叙述正确的是