BI

bi(1)

bi(2)

鼻 / always 鼻子 = nose

bi(3)

比 = to compare

比价格 = bi(3)jiau jia(4)ge = to compare prices

笔 / never with 子 = pen

bi(4)

必 / always 必须 bi(4)xu(1) = must

币 = currency

闭 / usually 关闭 guan(1)bi(4) / never used alone = to close