In the sentence “In some designs the cylinder oil is timed so that the oil injects only on the piston ring belt, the "piston ring belt" means （）.

[单选题]In some designs the cylinder oil is timed so that the oil injects only on the （）.A . piston crownB . piston grooveC . piston skirtD . piston ring belt

[单选题]A．fter seeing the good students’ designs，some students _________.A． 1oved their own designs moreB． thought they had a fair chanceC． put their own designs in a comerD． thought they would not win the prize

[单选题][ A] patterns[ B] designs[ C] plans[ D] schemes

[单选题]When the truth of sentence(a)guarantees the truth of sentence(b)and the fal

[单选题]Exhaust temperature increases in all cylinders, the possible cause may be（）(1) increased scavenging air temperature(2) air in fuel pumps and fuel valves(3) fouling of air and gas passagesA . (1)+(2)B . (1)+(3)C . (2)+(3)D . (1)+(2)+(3)

[单选题]（） supplies pilot air to control the cylinder air start valves.A . An air compressorB . An indicator cockC . An air distributorD . A safety valve

[单选题]C．H．ow Room Designs Affect Our Work and FeelingsA．rchitects have long had the feeling that the places we live in can affect our thoughts, feelings and behaviors. But now scientists are giving this feeling an empirical(经验的，实证的) basis. They are discove

[单选题]眼镜片商品标志，Cyl表示（ ）。A．球镜片B．柱镜片C．防紫外线D．近视镜

[单选题]眼镜片商品标志，Cyl表示（）。A . 球镜片B . 柱镜片C . 防紫外线D . 近视镜

[名词解释] 最小无限圆柱临界直径 minimum critical infinite　cylinder diameter