A well－lubricated bearing surface always appears__________.

_______ diesel engines generally have two systems of lubrication: a total loss system feeding and a circulating system lubricating the running gear and cooling the pistons.

Which of the listed cylinder liner surface conditions indicates proper lubrication？A.Dull

The function of lubricating oil is to ______.A.maintain even distribution of bearing wearB

Proper lubrication of the main bearings is more easily obtained in a single acting, four-s

Proper lubrication of the main bearing is more easily obtained in a single acting four－str

The return of wolves benefits the grizzly bears because______.A．wild fruits grew very well