【简答题】List four kinds of hetero atoms-containing compounds present in crude oil.
【单选题】操作机械时,护罩处于关闭位置,而护罩一旦处于开放位置,就会使机械停止运作,指的是下列( )的运作方式。
【单选题】If a credit states: “ PACKING LIST IN FOUR COPIES”, which of the following one is NOT correct?
A.
The packing list could be presented four copies.
B.
The packing list could be presented two originals and two copies.
C.
The packing list could be presented one original and three copies.
D.
The packing list could be presented four originals.
【判断题】每100克油脂所吸收的碘的克数,称为该油脂的碘值。
【单选题】操作机械时,护罩处于关闭位置,而护罩一旦处于开放位置,就会使机械停止运作.这种防护罩的运作方式指的是____的运作方式.
【单选题】普通 TTL 非门电路中,输入级二极管的作用在于( )。