New words：
default [di'fɔ:lt]
n.违约；拖欠；缺席；缺陷；默认；系统设定值，预置值
v.违约；拖欠；缺乏；不履行
Sample Sentences：
The team lost a game by default.
Some people could decide to default.
If they stop paying, that's called a default.
You can type a different name, or use the default name.
But not every Android phone uses Google's maps app by default.
If default happens and they are blamed, they will pay a terrible price.
New words：
fault [fɔ:lt] n. 故障；过错；过失；缺陷
Sample Sentences：
Every man has his faults.
It was not our fault that we were late.
Why should I say sorry when it's not my fault?
The teacher found many faults in spelling and grammar in my composition.
New words：
failure ['feiljə] n.失败；故障；失灵；倒闭
Sample Sentences：
The whole thing was a complete failure.
They blamed the failure of the action on George.
The new restaurant was a failure and soon closed.
The success or failure of the plan depends on you.
New words：
primary ['praiməri] adj.主要的；最重要的；基本的；最初的；初级的
Sample Sentences：
The little boy left primary school at eleven.
Food and water are primary wants of human life.
A primary cause of Tom's failure is his laziness.
He only accepted the primary education off and on in his childhood.
failure ['feiljə] n.失败；故障；失灵；倒闭
New words：
volunteer [.vɔlən'tiə]
n.志愿者；志愿兵；义务工作者；自告奋勇者
v.自愿做；义务做
Sample Sentences：
The soldier volunteered for guard duty.
They volunteered to repair the house for the old lady.
Can I have a volunteer to wash the dishes?Volunteers were ready and waiting to pack the food in boxes.