问题 选择题

细菌和真菌分布广泛,无处不在,与人类关系密切.下列叙述错误的是(  )

A.制酱离不开霉菌

B.细菌和真菌能引起食品腐败

C.真菌能产生抗生素

D.人类肠道中的细菌都是有害的

答案

A、制酱要用到霉菌,霉菌发酵把有机物分解成氨基酸等物质,利于人体的吸收和提高食品的鲜度,不符合题意.

B、各种细菌、真菌等微生物,接触到食物,并利用食物上的有机物发育繁殖.期间会产生很多的生长代谢产物,产生各种各样的味道,如酸、臭等等.因此食物腐败变质是由于微生物的生长和大量繁殖而引起的.不符合题意.

C、有的真菌能引起多种疾病,有的真菌却可以产生杀死某些致病细菌的物质,这些物质被称为抗生素,如青霉素是一种著名的抗生素,它是由真菌中的青霉菌产生的,不符合题意.

D、大肠杆菌是人和许多动物肠道中最主要且数量最多的一种细菌,一般不致病,但一些特殊血清型的大肠杆菌对人和动物有病原性,尤其对婴儿和幼畜(禽),常引起严重腹泻和败血症.人们在大肠杆菌中转入合成胰岛素的基因,可以生产人们需要的胰岛素,这是对其的利用方面.符合题意.

故选:D

填空题
阅读理解

Some British and American people like to invite friends for a meal at home. You should not be upset if your English friends don't invite you home. It doesn't mean they don't like you! Dinner parties usually start between 7 and 8 p.m., And end at about 11. Ask your hosts what time you should arrive. It's polite to bring flowers, chocolates or a bottle of wine as gift. Usually the evening starts with drinks and snacks. Do you want to be extra polite? Say how much you like the room, or the pictures on the wall. But remember---- it's not polite to ask how much things cost. In many families, the husband sits at one end of the table and the wife sits at the other end. They eat with their guests.

You'll probably start meal with soup or something small, and then you have meat of fish with vegetables, and then desert, followed by coffee. It's polite to finish everything on your plate and have more if you want it. Did you enjoy the evening? Call your host and hostess the next day, or write them a short "thank you" letter. British and American people like to say "thank you, thank you, thank you" all the time!

小题1:You're not invited to the evening by a friend, which              .

A.means you are not welcome f or some bad manners

B.means he or she doesn't like you for some unknown reasons

C.means you should pay more visits to them and bring more gifts

D.doesn't mean he or she doesn't like you小题2:You should never              .

A.say you like the host's house very much

B.ask the host the price of the things in the house

C.have drinks and some snacks before the evening

D.sit beside the host or hostess when having dinner小题3:As a guest, you should finish everything to show              .

A.you are healthy

B.you rea lly like the food

C.you like cooking

D.you have a good appetite.(胃口)