Questions & Answers about Пока ты ждёшь такси, можно почитать журнал.
Because the sentence starts with a subordinate clause introduced by пока (while). In Russian, a subordinate clause is separated from the main clause by a comma:
- Пока ты ждёшь такси, = subordinate clause
- можно почитать журнал = main clause
If you reverse the order, you still use a comma: Можно почитать журнал, пока ты ждёшь такси.
Here пока means while / as long as (introducing a time clause). It can also mean for now / bye for now / until then in other contexts, for example:
- Пока! = Bye!
- Пока не поздно = Before it’s too late / While it’s not too late