Chinese has two number twos

Where the picture shows up in 二/两

1. 1

   the 2 on a label

   我住十二楼，请按一下。

   wǒ zhù shí'èr lóu, qǐng àn yíxià

   I'm on the twelfth floor — could you press it?

2. 2

   two of a thing

   老板，来两杯冰美式。

   lǎobǎn, lái liǎng bēi bīng měishì

   Two iced americanos, please.

3. 3

   two units of time

   我等了两个小时，他还没来。

   wǒ děng le liǎng ge xiǎoshí, tā hái méi lái

   I waited two hours and he still hasn't turned up.

   Two o'clock is 两点, never 二点.

4. 4

   the 2 that ranks

   前面第二个路口右转。

   qiánmiàn dì-èr ge lùkǒu yòu zhuǎn

   Turn right at the second corner ahead.

   After 第 it is always 二. 第两个 does not exist.

5. 5

   two before a big unit

   这个包两千八，能便宜点儿吗？

   zhège bāo liǎng qiān bā, néng piányi diǎnr ma

   This bag is 2,800 — could you come down a little?

   Use 两 before 千 and 万; before 百 the standard form is 二百.