zì jǐ chí dào bǐ jiào jiǔ shí kě yǐ shuō nǐ men xiān kāi shǐ bú yòng děng wǒ

自己迟到比较久时，可以说“你们先开始，不用等我”。

When you are quite late, you can say 'You guys start first, don't wait for me.'