二力构件的受力特点是（）A．所受的两个力必相互垂直 B．所受的两个力必相互平行 C．

2012年12月11日，当当网公布莫言书籍从其获奖到领奖期间的销售数据称，60天里作品《蛙》销售了80余万册。小张在网上以18元团购了一本标价23元的莫言小说《蛙》，对此说法正确的是                             （       ）

①23元是观念中上的货币，执行的是价值尺度职能  

②23元是现实的货币，反映的了书本的价值  

③18元是观念上的货币，执行的是支付手段的职能  

④18元是现实的货币，执行的是流通手段的职能

A．①③

B．①④

C．②③

D．②④

在横线处填上恰当的关联词，使上下文连贯起来。

　　____①____不培养坚强的性格和不怕困难的精神， ____②____，____③____懂得很多好道理，____④____未必真有用处，____⑤____正像温室里的花卉似的，是经不起日晒雨淋的。

______________________________

现代营销战略的核心可以称为STP营销，下面不属于STP营销的是( )。

A．市场分析

B．选择目标市场

C．细分市场

D．产品定位

Are you interested in seeing the beautiful fall foliage of New England but tired of traffic jams and overbooked hotels Then this year forget the crowds in New England and see the beautiful colors of autumn in the Catskills.
These rugged mountains in New York State, just 90 miles northwest of New York City, are famous for the legendary tales of Rip Van Winkle, and more recently for the summer hotels mat sprang up in the region during the 1940s, 1950s, and 1960s. Families trying to escape the heat of New York City found the Catskills to be the perfect place to stay for a month or so each summer. By the late 1950s there were over 500 resorts and hotels offering nighttime entertainment as well as all kinds of outdoor activities. Famous comedies like Jackie Gleason, Joan Rivers, and Sid Caesar all got their start touring the hotel clubs here. Since the introduction of air-conditioning and cheaper air travel, however, families have stopped coming to the Catskills in such large numbers, chasing instead more distant locations at different times of the year. Many of the Catskills hotels closed in the 1970s, but some remain and have expanded and changed their facilities to meet the needs of today’s visitors.
Currently, there are many activities available to the traveler besides witnessing the changing colors of the leaves. There is an all-organic sheep farm where visitors can see how a traditional sheep farm operates. There are also hundreds of miles of scenic drives in the area. Route 42, for instance, is an excellent site for spotting bald eagles. For more information on vacations in the Catskills, call the office of Public Information.

The author’s main purpose is to ______.

A. promote the Catskills as a vacation destination
B. introduce visitors to famous Catskills entertainers
C. describe the history of the Catskills region
D. compare the Catskills to New England

活塞式压缩机上止点间隙也被称为（）。

A.阀腔空间

B.环形间隙

C.顶部间隙

D.搭口间隙