离心泵的出口阀不能（）。 A.调节流量 B.调节扬程 C.防止水倒流

Shoppers who carefully plan their visit to the grocery store can save money on their grocery bills. Shopping when not (61) , sticking to their grocery list, and (62) a few simple rules will cut down the grocery bill.

Shoppers should visit the grocery store on a full stomach by planning their trip (63) after a large meal. If that’s not (64) , they should find something (65) to eat on while preparing a grocery list. Most shoppers are less likely to buy extras when they are not troubled by (66) .

Although having a list and (67) to it is the most important factor in saving money, (68) must prepare lists wisely in order to (69) . A carefully planned list should (70) in season produce and any items on (71) or discounted through coupons. Many special buys are announced through the local newspapers, so buying the "grocery issue" is (72) the money you spend. (73) , it’s important to remember that many newer, more expensive products first offered through coupons may not (74) enough savings for shoppers to give up products they usually buy.

Now that the shopper has (75) the grocery list, it’s time to leave for the store. However, no preparations are complete without a pocket calculator or a piece of paper and a (76) to figure costs.

Once at the store, the shopper who wants to save money should follow a few more rules. The shopper should not stay (77) than necessary because bills go up each minute the shopper is in the store. So, (78) a time limit and a cost limit can hold down the (79) . Of course, the shopper should stick strictly to the (80) and not buy any extras. If the grocery list is a short one, shoppers can use the small hand-held basket instead of the roomy grocery cart.

63（）

A．shops

B．hunger

C．money

D．work

设a＞0，则

=______．

当今时代的主题是 [ ]

A．合作与竞争

B．合作与冲突

C．和平与发展

D．战争与和平

汉译英：“途经口岸；处理日期”，正确的翻译为：( )

A．Port of call; Date of departure

B．Port of discharge; Date of departure

C．Port of call; date of treatment

D．Port of discharge; Date of treatment

步进电动机式是经济型数控机床按驱动和定位方式划分。