These are all words for a small area of dirt or another substance on a surface.以上各词均指污点、斑点、污迹。
mark a small area of dirt or other substance on the surface of sth, especially one that spoils its appearance指污点、污迹、斑点：◆The kids left dirty marks all over the kitchen floor.孩子们把厨房的地板弄得污迹斑斑。
stain a dirty mark on sth that is difficult to remove, especially one made by a liquid指污点、污渍：◆blood stains血迹
fingerprint a mark on a surface made by the pattern of lines on the end of a person's finger, often used by the police to identify criminals指指纹、指印：◆Her fingerprints were all over the gun.那支枪上布满了她的指纹。
streak a long thin mark or line that is a different colour from the surface it is on指条纹、条痕：◆She had streaks of grey in her hair.她头上已是白发绺绺。
speck a very small mark, spot or piece of a substance on sth指小点、污点：◆There isn't a speck of dust anywhere in the house.整间房子一尘不染。
blot a spot or dirty mark left on sth by a substance such as ink or paint being dropped on a surface指污点、墨渍
smear a mark made by sth such as oil or paint being spread or rubbed on a surface指污迹、油渍、污渍、污点
spot a small dirty mark on sth指污迹、污渍、污点：◆There were grease spots all over the walls.墙上满是油渍。
Patterns
a streak/speck/blot/smear/spot of sth
a greasy mark/stain/smear
an ink mark/stain/blot/spot
a grease mark/stain/spot
to leave a mark/stain/fingerprint/streak/speck/blot/smear