大小正好
dàxiǎo zhènghǎo
The size is just right.
正好合适
zhènghǎo héshì
It fits exactly.
我正好有空
wǒ zhènghǎo yǒu kòng
I happen to be free.
他正好来了
tā zhènghǎo lái le
He happened to arrive.
