Learn the Difference between “次(cì)” and “遍(biàn)”

Bìngrén: Yīsheng, zhèzhǒng yào zěnme chī?
病人:         医生，  这种         药    怎么    吃？
Patient: Doctor, how is this medicine to be taken?
Yīsheng: Yìtiān chī sān___,  yí __chī liǎngpiàn.
医生:        一天   吃  三  ___，一__吃   两片。
Doctor: Take the medicine three times a day and two pills each time.
A. 次(cì)；遍(biàn)
   
B. 遍(biàn)；遍(biàn)
   
C. 次(cì)；次(cì)
   

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.
Examples
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).”
Examples
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.