割草机的消声器就是一个包含至少两个子系统的系统：一具保护性外套和多孔的吸收材料。

A、对

B、错

David, my neighbor, has two young kids who are five and seven. One day he was【C1】___\_his seven-year-old son Kelly how to push the lawn mower(割草机)around the yard. As he was telling him how to turn the mower【C2】___\_, his wife, Jan, called to him to ask a question. As David answered the question, Kelly pushed the lawn mower【C3】___\_through the flower bed at the edge of the lawn—【C4】___\_a two-foot wide path leveled to the ground! When David turned back and saw what had happened, he began to lose【C5】___\_. David had put a lot of time and【C6】___\_into making those flower beds the【C7】___\_of the neighbourhood. As he began to【C8】___\_his voice to his son, Jan walked quickly over to him, put her hand on his shoulder and said, "David, please remember we are raising children, not【C9】___\_!" Jan【C10】___\_me how important【C11】___\_is as a parent to remember our priorities(things that need attention before others). The window shattered(打碎)by a【C12】___\_, a lamp knocked over by a careless child, or a plate dropped in the kitchen are already【C13】___\_. The flowers are already dead. We must remember not to【C14】___\_to the destruction by breaking a childs spirit and deadening his【C15】___\_. A few weeks ago Mark Michaels, the owner of a store, and I were together【C16】___\_parenting. He told me while his family were out for dinner, his daughter knocked over her water glass.【C17】___\_the water was cleaned up without any blaming remarks from her parents, she looked up and said, "I【C18】___\_want to thank you for not being like other parents. Most of my friends parents【C19】___\_have shouted at them and given them a lecture about paying more attention. Thanks for not【C20】______that!"

【C1】

A．teaching

B．helping

C．looking at

D．asking

抽览姜吵雄慌屿品款．下列选项中即玉澡脉况券石找似百差献，可以申请外观设计专利的是遵哗暴抚淘许割猪异（围墓涉释）

A、一种新的调味品

B、一种糖尿病的治疗方法

C、一种造型独特的割草机

D、一幅美术作品

堤防工程管护常用小型机械设备不包括()。

A.混凝土拌和运输车

B.割草机

C.小翻斗车

D.小型推土机

伊恩在完全竞争的修剪草坪行业中提供服务。他的固定成本是每天7美元(租割草机的成本)，可变成本如下表所示。

a．伊恩的生产总成本是多少？在表中“总成本”一栏填写。b．计算每次修剪草坪的市场价格为9美元时伊恩的利润。如果修剪草坪的市场价格是每次9美元，那么伊恩会修剪多少草坪？他的利润是多少？他在短期中会继续修剪草坪么？c．计算每次修剪草坪的市场价格为3．60美元时伊恩的利润。如果修剪草坪的市场价格是每次3．60美元，那么伊恩会修剪多少草坪？他的利润是多少？他在短期中会继续修剪草坪么？

共用题干Can Loud Music Cause Hearing Impairment（损伤）?
Have you ever gone to a concert and realized that your seats were right next to the
booming speakers?Are you guilty_________(1)turning up the volume on your portable
cassette or CD player to drown out the whining（哭哭啼啼）of your little brother?
Sometimes it's difficult to avoid loud music or noises,but they can be bad news because
loud noises can_________(2)temporary or permanent hearing loss.
Extremely loud music and noises that go on for long periods of_______(3)are
common causes of deafness.If a noise is so loud that you have to shout to make yourself
_______(4),there is a______(5)that the mechanism inside your ear can be
injured.
Temporary hearing loss can happen after you've been_______(6)to loud noise
for only 15 minutes.If you have temporary hearing loss,you won't be able to hear as
________ (7) as you normally can, and you may have tinnitus（耳鸣）,which is a
fancy word for ringing in the ears. Your ears can feel"full",too._________（8),
these things usually go away and your hearing soon returns to normal.
Permanent hearing loss can happen when someone is exposed to loud noise
________(9)and over. Construction workers and people who work in factories must
________(10)ear protectors because the equipment they use can be extremely loud.
But even some lawn mowers（割草机）and power tools can permanently__________
(11)a person's ability to hear high-pitched noises and can also give him permanent tinnitus.
Listening to extremely loud music over and over can also have the same effect on a person's
______(12).And using headphones on a portable cassette or CD player can be
dangerous________(13)if the volume is too high and the headphones are used a lot,
the noise can damage the ears.
The best way to avoid hearing loss is to wear ear protectors when working with
machinery and earplugs when going to a_________(14).Headphones are OK to wear
when you're listening to music;just be sure the volume isn't too high,and give them a rest
________(15)once in a while. _________(8.)A: Unfortunately B: Accordingly C: Luckily D: Unexpectedly