Blood is the red liquid that flows inside your body, which you can see if you cut yourself.
His shirt was covered in blood.
他的衬衫沾满了血。
You can use blood to refer to the race or social class of someone's parents or ancestors.
There was Greek blood in his veins: his ancestors originally bore the name Karajannis.
他有希腊血统——他的祖先原来姓卡拉扬尼斯。
bad blood
If you say that there is bad blood between people, you mean that they have argued about something and dislike each other.
There is, it seems, some bad blood between Mills and the Baldwins.
米尔和鲍德温两家看上去好像有积怨。
in cold blood
If something violent and cruel is done in cold blood, it is done deliberately and in an unemotional way.
The crime had been committed in cold blood.
这起案件是蓄意犯罪。
blood on one's hands
If you say that someone has a person's blood on their hands, you mean that they are responsible for that person's death.
He has my son's blood on his hands. I hope it haunts him for the rest of his days.
他应该对我儿子的死负责,但愿他终生不得安宁。
in one's blood
If a quality or talent is in your blood, it is part of your nature, and other members of your family have it too.
Diplomacy was in his blood: his ancestors had been feudal lords.
他的外交能力是天生的:他的祖上曾是封建王侯。
new blood , fresh blood , young blood
You can use the expressions new blood, fresh blood, or young blood to refer to people who are brought into an organization to improve it by thinking of new ideas or new ways of doing things.
There's been a major reshuffle of the cabinet to bring in new blood.
内阁进行了重大改组以吸纳新生力量。