255.Trichloroethylene is a health hazard.

　Trichloroethylene is good for health.

　Trichloroethylene is hazard for health.

　When there is trichloroethylene, you shouldn't worry about it.

正确答案：B

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517.IF YOU PULL THE EJECTION SEAT HANDLE, THE SEAT WILL ( ).

516.这种材料接触热表面时会释放出危险的气体。

515.为了便于阅读和交叉参考,如果可行的话、插图、图形和表格应以垂直布
局显示

514.Units of measurements shown in manual must be consistent where
practical.

513.MAKE SURE THAT THE SPEEDBRAKE RETRACTS IMMEDIATELY.

512.An important occurrence that can cause damage or have dangerous
results.

511.Put the blanking caps on the open ends of the telescopic duct and
the slat duct.

510.The loading conditions together with the resulting margins of safety
were evaluated.

509.The effects of corrosion have not been considered in the rationale
in selecting inspection times or in the effects on the fatigue stresses.

508.Use this alternative procedure if during the test the flow indicator
does not reach the predetermined position.