In Chinese, a classifier is special and some classifiers are easily confused in meaning and usage, like “次(cì)” and “遍(biàn).”
“次(cì)” and “遍(biàn)” both can be used to describe frequency or how many times you have done something. However, “次(cì)” emphasizes the frequency of a repeated action rather than the completion of an action or the time spent in performing an action.
Wǒ qùguò liǎngcì BěiJīng.
我 去过 两次 北京。
I have been to Beijing twice.
Wǒ zuòguò sāncì fēijī.
我 坐过 三次 飞机。
I have taken an airplane three times.
“遍(biàn)” emphasizes the amount of time spent doing something and also the completion of an action. So when we focus on the time it takes to do an action and complete an action, we use “遍(biàn).”
Nà bù diànyǐng wǒ kàn le liǎngbiàn.
那 部 电影 我 看 了 两遍。
I watched the film twice.
Wǒ měitiān dú sānbiàn dāncí.
我 每天 读 三遍 单词。
I read vocabulary three times a day.
In our test above, the doctor wants to stress the frequency of taking the medicine each day rather than stress the completion of taking the medicine or the time spent taking the medicine, so we should use “次(cì)” in the two blanks.
You may be also confused about the other group of Chinese phrases: