jīn tiān hǎo rè ā
Simon: 今天好热啊!
It’s so hot today!
shì ā wǒ men jiào shàng dà lǐ qù yóu yǒng ba
Xiao Lin: 是啊,我们叫上大李去游泳吧。
Yeah, let's ask Da Li to go swimming.
bú guò tīng shuō tā shì gè hàn yā zǐ
Simon: 不过听说他是个旱鸭子。
But I heard he is a "Dry Duck".
ā ,nà suàn le ba ,wǒ men zǒng bú néng “gǎn yā zǐ shàng jià ”ba
Xiao Lin: 啊,那算了吧,我们总不能“赶鸭子上架”吧。
Ok, forget it. We can't drive a duck onto a perch
In the dialogue, Xiao Lin complains that it is hot, and Simon suggests inviting Da Li to go swimming with them. Xiao Lin responds with concern that Da Li can't swim, and jokingly calls him a "旱鸭子"(hàn yā zi), which literally means a "Dry Duck". "旱鸭子" refers to those ducks which are raised on land and never swim, so "旱鸭子" is a metaphor for people who can' t swim.
Therefore, Simon has to give up his idea, and he reluctantly says he can't "赶鸭子上架". "赶鸭子上架" is a Chinese phrase literally meaning "drive a duck onto a perch" (The western equivalent is saying you can’t lead a horse to water). This phrase is usually used to refer to "forcing someone to do something beyond his/her ability."