一支笔
yì zhī bǐ
One pen
我的笔
wǒ de bǐ
My pen
一笔写完
yì bǐ xiě wán
Write it in one stroke
这一笔错了
zhè yì bǐ cuò le
This stroke/entry is wrong
一笔交易
yì bǐ jiāoyì
One transaction/deal
一笔生意
yì bǐ shēngyì
One business deal
