已知α1=(1,4,0,2)T,α2=(2,7,1,3)T,α3=(0,1,-1,a

题型:填空题

问题:

已知α1=(1,4,0,2)T,α2=(2,7,1,3)T,α3=(0,1,-1,a)T,β=(3,10,b,4)T.若β不能由α1,α2,α3线性表出,则a,b应满足的条件是______.

考点:普通考研考研数学(二)考研数学二
题型:填空题

Rhinos(犀牛) are big and can be dangerous. They are also shy and seldom seen. Once there were hundreds of rhino species, but today there are only five. One ancient rhino called Indricotherium was the largest land mammal that ever lived. It was 5m high at the shoulders, and 8.5m long— twice the size of today’s biggest elephant! The living rhinos are still big, averaging 2-3m long and weighing up to 3,600kg.

To see all five species of living rhino you would need to do a bit of exploring. First you might visit Africa for a look at the white rhino and the black rhino. They live in Africa’s dry woodlands and grasslands. Then you could head to India and Nepal for a look at the Indian rhino. It lives in the high grasslands near rivers, where you have to ride an elephant to find one. Finally you might travel to the rainforests on the islands of Indonesia to see the Sumatran and Javan rhinos. These are the smallest and rarest rhinos in the world and extremely difficult to find.

Most rhinos are gentle and timid (胆小的).They have a bad reputation for being very aggressive, but that may be partly because they get frightened easily. Also, they have poor eyesight. They rely on their strong sense of smell to tell them a stranger is approaching, but if the wind is blowing the wrong way, they may not know someone is there until it’s too late.

Rhinos can be found only in their habitats, which is why habitat destruction has caused rhino populations to decline. As they disappear from certain places, their absence leads to many changes to the landscape. For example, black rhinos in Africa only eat shrubs (灌木) and small trees, pruning (修剪) the plants and limiting their growth. Many other species benefit from this, and as rhinos disappear, so do many other animals sharing their habitat. Bushes and trees take over the land and force species like the antelope to leave in search of food. In a short time the whole habitat has changed.

小题1:          From the text we learn that ______.

A.rhinos are all big and dangerous

B.rhino numbers have declined greatly

C.rhinos are twice as large as elephants

D.Indricotherium is the world’s biggest living animal now小题2:          The white rhino can be found in______.

A.Indonesia’s island

B.Nepal’s high grasslands

C.Africa’s dry woodlands and grasslands

D.India’s high grasslands near rivers小题3:          What can we conclude from Paragraph 2?

A.Most rhinos live alone.

B.Rhinos are disappearing from their habitats.

C.The five rhino species are all different in colour.

D.Rhinos’ habitat ranges from rainforests to grasslands.小题4:          The underlined word “aggressive” in Paragraph 3 can be replaced by_____.

A.energetic

B.attractive

C.useless

D.fierce小题5:          The example of the black rhinos in the last paragraph is mainly to show that_____.

A.rhinos only eat plants

B.all rhinos are endangered

C.all the habitat of rhinos has been damaged

D.the disappearance of rhinos has led to habitat change

题型:填空题

设备的三级保养为日常保养、一级保养、二级保养。

题型:填空题

某校园工程结构裂缝现象研究报告关于墙面裂缝说法错误的是()

A.几乎所有工号的全部外墙面从底层到顶层均出现裂缝现象。

B.网状裂缝只出现在抹灰层和涂料面上。

C.倾斜裂缝会深及砖砌填充墙体。

D.内墙面裂缝出现几率较高。

题型:填空题

在( )的情况下,企业年金个人账户可由原管理机构继续管理。

A.员工升学

B.员工死亡

C.员工参军

D.新就业单位没有实行企业年金制度

E.员工失业

题型:填空题

企业的成功是跟企业做大有关的。

更多题库