input: The clause can be drafted as follows
fixed: The clause can be drafted as follows:

input: Drink at least 1 litres of pure water every day
fixed: Drink at least 1 litres of pure water every day.

input: His doctoral thesis is an important contribution to conformal mappings of multiply connected plane domains
fixed: His doctoral thesis is an important contribution to conformal mappings of multiply connected plane domains.

input: During this period the Jews were just followers of a religion which had to be accepted along with other religions
fixed:
During this period the Jews were just followers of a religion, which had to be accepted along with other religions.