下列关于摩擦力的说法正确的是( ) A.摩擦力大小总是与正压力成正比 B.静摩擦

题型:选择题

问题:

下列关于摩擦力的说法正确的是(  )

A.摩擦力大小总是与正压力成正比

B.静摩擦力是不可能使物体运动的

C.摩擦力的大小总是与接触面的粗糙程度有关

D.无论是滑动摩擦力还是静摩擦力都可以是动力

考点:静摩擦力
题型:选择题

下列属于社会行为的是(  )

A.两只狗为争享一块骨头而打架

B.一条蛇在追捕一只青蛙

C.一支威猛的头羊领导着羊群

D.母鸡在喂食小鸡

题型:选择题

右图是生态系统4种组成成分的关系图解,图中的B是二氧化碳.请据图回答:

(1)本生态系统中的能量流动是从A______固定太阳能开始的.

(2)此系统中连接生物界与无机环境的是______.

(3)图中A→B的过程是通过______实现的;B→A的过程是通过______实现的.

(4)图中能参与构成食物链的是______和______.

(5)碳在生态系统中主要以______形式循环的.

题型:选择题

1 Day Fly-Fly Aboriginal Rock Tour

Tour Details

Operator: Adventure North Australia

Destination: Cooktown

Departs From: Cairns

Tour Description

Voted as one of Australia's Must-Do-Experiences. Treat yourself to an amazing day out with Aboriginal Elder Willie Gordon.

Depart Cairns Domestic Airport for the Skytrans Flight to Cooktown. Flight departs Cairns at 6:45 a.m.

Enjoy a 45-minute flight with wonderful views from Cairns to Cooktown as you fly along the coast between the World Heritage rainforest and the Great Barrier Reef. On arrival in Cooktown you will be met by Willie Gordon, the traditional storyteller of the Nugal-warra clan(部落).

Willie Gordon takes guests to his ancestral rock art sites, set high in the hills above Hope Vale, outside Cooktown. Here he shares the stories behind the art, and explains how the paintings speak of the most basic and important quality of life and the knowledge of his people.

The tour takes you through an impressive view of six rock art sites, including an ancestral Birth Cave and the Reconciliation Cave. This includes a 30-minute bush walk on generally easy terrian(地形). (Covered closed-on shoes must be worn.)

Return to Cooktown at 1:15 p.m. where Willie will take you to the Nature Power House Museum, Cooktown's Visitor Information Centre. Lunch is included at the Verhandah Cafe.

The rest of the afternoon is free to explore historical Cooktown before your transfer to Cooktown airport and return flight to Cairns. Flight arrives at Cairns Domestic Airport at 6:40 p.m. Own arrangements on arrival in Cairns.

Prices

Adults: $ 549.00

Children: $ 390.00

Families(2 adults and 2 children): $ 1,869.00

小题1:According to the passage, how will tourists arrive in Cooktown?

A.By ship.

B.By car.

C.By air.

D.By train.小题2:What do we learn about Willie Gordon?

A.He acts as the guide of the tour.

B.He is the owner of the Verhandah Cafe.

C.He works in the Nature Power House Museum.

D.He is the manager of Adventure North Australia.小题3:After viewing rock art, tourists will go to__________.

A.the World Heritage rainforest

B.the Great Barrier Reef

C.rock art sites outside the town

D.the Nature Power House Museum小题4:We learn from the passage that the whole trip lasts about__________.

A.six hours

B.eight hours

C.ten hours

D.twelve hours小题5:From the passage, the tour is designed to let the tourists__________.

A.learn about the custom

B.enjoy the ancient art

C.taste the delicious snacks

D.experience the lifestyle

题型:选择题

率先推出外汇期货交易,标志着外汇期货的正式产生的交易所是()

A.芝加哥商品交易所

B.芝加哥期货交易所

C.国际货币市场

D.美国堪萨斯农产品交易所

题型:选择题

下列关于交流弧焊机的安全要求中,说法不正确的是()。

A.交流弧焊机外壳应可靠接地

B.交流弧焊机二次、二次电源线可采用铜芯橡皮电缆

C.交流弧焊机一次线长度不宜超过2~3m

D.在电击危险性大的环境作业,弧焊机二次侧不宜装设熄弧自动断电装置

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