GB17930无铅车用汽油中规定无铅车用汽油的实际胶质允许用GB/T509方法测定,仲裁试验以()测定为准。
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用于钢筋混凝土的水泥的氯离子含量不宜大于()%,用于预应力混凝土的氯离子含量不宜大于()%。
The four strokes are called suction, compression, expansion and exhaust, but only () stroke provides the power to drive the ship.
A. suction
B. compression
C. expansion
D. exhaust