（）是指交易者同时买入或卖出相同品种不同交割月份的外汇期货合约，以期合约间价差朝有利方向发展后平仓获利的交易行为。

A交易主体以双边授信为基础

B交易双方协商确定价格

C交易主体以中国外汇交易中心为交易对手方

D交易双方自行安排资金清算

A财务风险

B经营风险

C非系统性风险

D系统性风险

1.[单选题]____

A.Her friend Erika.

B.Her little brother.    

C.Her grandfather.

D.Her grandmother.

2.[单选题]____

A.By taking pictures for passers-by.      

B.Her little brother.                  

C.Her grandfather.

D.Her grandmother.

1.[单选题]____

A.Her friend Erika.

B.Her little brother.

C.Her grandfather.

D.Her grandmother.

2.[单选题]____

A.By taking pictures for passers-by.

B.By working part time at a hospital.

C.By selling lemonade and pictures.

D.By asking for help on social media.

A需求曲线不变，供给曲线左移

B需求曲线不变，供给曲线右移

C供给曲线不变，需求曲线左移

D供给曲线不变，需求曲线右移

1.[单选题]______

A.The discovery of a new species of snake.

B.The second trip to a small remote island.

C.The finding of 2 new species of frog.

D.The latest test on a rare animal apecies.

2.[单选题]______

A.A poisonous snake attacked him on this field trip.

B.He discovered a rare fog on a deserted island.

C.A snake crawled onto his head in his sleep.

D.He fell from a tall palm tree by accident.

3.[单选题]______

A.From its genes

B.From its length

C.From its origin

D.From its colour