Meaning of dà gài:
大概
roughly; probably; rough; approximate; about; general idea
Wǒmen dàgài zài xiàwǔ sān diǎn dàodá.
我们大概在下午三点到达。
We will probably arrive around 3 PM.
Tā jīntiān dàgài bù huì lái.
他今天大概不会来。
He probably won't come today.
Wǒmen dàgài huì zài wǔ diǎn dàodá.
我们大概会在五点到达。
We will probably arrive at five o'clock.
Tā dàgài xūyào liǎng gè xiǎoshí wánchéng zhè fèn gōngzuò.
他大概需要两个小时完成这份工作。
He will approximately need two hours to complete this task.
Wǒ dàgài xūyào bàn xiǎoshí dàodá nàlǐ.
我大概需要半小时到达那里。
I will need about half an hour to get there.
Wǒ duì zhè jiàn shìqíng yǒu gè dàgài de liǎojiě.
我对这件事情有个大概的了解。
I have a general idea of this matter.