单项选择题
A.speed B.friction C.impact D.atmosphere
Emulsion oils and sodium nitrite are both approved addi...
单项选择题Emulsion oils and sodium nitrite are both approved additives, but （） cannot be used if any pipes are galvanized or if soldered joints exist.
A.the latter B.latter C.former D.the former
单项选择题Emulsion oils and sodium nitrite are both approved additives, but the latter cannot be used if any pipes are （） or if any soldered joints exit.
A.chromed B.welded C.galvanized D.bolted
Either a low injection pressure or a leakage of piston ...
单项选择题Either a low injection pressure or a leakage of piston rings is able to lead （）.
A.a high exhaust temperature B.a high smoky exhaust C.a high output D.a high compression
