x的2倍与3的差可表示为______．

某温度下，在一个2 L的密闭容器中，加入4 mol A和2 mol B进行如下反应：3A(g)+2B(g) 4C(?)+2D(?)。反应一段时间后达到平衡，测得生成1．6 mol C，且反应的前后压强之比为5：4(相同的温度下测量)，则下列说法正确的是(          )

A．该反应的化学平衡常数表达式是

B．此时，B的平衡转化率是35％

C．增大该体系的压强，平衡向右移动，化学平衡常数增大

D．增大C，B的平衡转化率不变

Many people like to eat at a favorite restaurant on their birthday.   71  Here are the tips about how to eat for free on your birthday.

Notice promotional (促销的) cards or signs at restaurants for their e-club or online notification of special offers. Sometimes it is called a birthday club. In some cases they ask for your email address and at other times, you register online from your own computer.   72 

If you don’t know whether your favorite restaurant has an e-club, look them up online. Just search their name if it’s a chain. Look over the webpage for anything that says SIGN UP or JOIN. It may call it an e-club.

You will receive e-mail advertisements from them.   73  if it asks for birthday and anniversary dates when you sign up, then the restaurant usually will send you a personal coupon and invitation for that event.

Check your e-mail the week leading up to your birthday. All the e-clubs that you signed up for will be sending their invitations.

Read the fine print on all the offers before deciding where to eat on your birthday. Some are only on the exact date.   74  There may be other requirements, like free dessert when you buy an entree (主菜).

Choose the most inviting offer or over several days, take advantage of free dining opportunities. __75 

A．Anyway, look around for these offers and get signed up.

B．However, others may be for any time over a two-week period.

C．But how can we eat better in a free restaurant?

D．It would be an even greater treat if the meal or part of the meal were free.E.      Why not celebrate your birthday for a whole week, not just one day?

F.      Often the advertisements will include discount coupons(优惠券).

G.     So don’t go to such restaurant.

肝胰襞是由（）或（）从腹后壁行向小网膜时所致的腹膜皱襞。

急性肠梗阻引起的水电解质紊乱为（）

A.代谢性酸中毒伴低钾、低钠

B.代谢性碱中毒伴低钾、低钠

C.代谢性酸中毒伴高钾、低钠

D.代谢性碱中毒伴低钾、高钠

E.以上都不正确

民俗由（）和风俗（customs）组成，全体生活的需要。

A、民间

B、人间

C、上流社会

D、万物