213.The door is made of carbon fiber reinforced plastic.

A. Use the specified one if theequivalent material is not available.

B. Use the available equivalent one if no material is specified.

C. If you can not get the specified material,use an equivalent.

A. Release the hydraulic pressure in the accumulator.

B. Release the power pressure in the accumulator.

C. Release the hydraulic pressure in the actuator.

A. Put on the electrical power.

B. Energize the ground service network.

C. Pressurize the ground service network.

A. 确认减速板能够立即收回。

B. 确保速度刹车立即缩回。

C. 确保减速制动器立即断开。

A. 在地面上的停放点贴上胶带。

B. 在地面上通过系留点贴上警示带。

C. 将绳索通过系留点连接到地面。

A. The Boeing 747 symbolizes the beginning of a new ear in air transport.

B. The Boeing 747 is the first type of airplane in air transport.

C. Modern air transport started from the Boeing 747.

A. 在可能的地方,将分号从定义和核准示例文本中删除是可行的。

B. 在可能和不得已的情况下,将标记符号从定义和示范示例的文本中删除。

C. 在可能和可行的情况下,将引号从定义和批准示例的文本中删除。

A. A mixture of fuel and oxygen can cause an explosion.

B. A mixture of fuel and nitrogen can cause an burn.

C. A mixture of gas and oxygen should cause an explosion.

A. This is the portion of the systems used to generate,regulate,control,and indicate AC electrical power.

B. Here is that portion of the systems used to generate,regulate,control,and indicate AC electronic power.

C. That is the portion of the systems used to generate,increase,control,and indicate AC electrical power.

A. 批准的形容词以其基本形式给出,在实际应用的过程中,在括号标注内其最高级和比较级形式。

B. 批准的形容词以其基本形式给出,在适用的情况下,其比较级和最高级形式要标注在括号内。

C. 形容词会以其批准的基本形式给出,在适当的时候,也可给出其比较级和最高级形式。

D. C.形容词会以其批准的基本形式给出,在适当的时候,也可给出其比较级和最高级形式。