I don't know a word in English / I check on the internet.
(When , If) I don't know a word in English, I check it on the internet.
I feel sleepy / I work all day.
I feel sleepy (when, after) I work all day.
I go to the gym / I eat a big breakfast.
(First, Before, After) I go to the gym (before , after , then) I eat a big breakfast.
I have an important test / I study the important topics.
(Before, When) I have an important test, I study the important topics.
I stop working and breathe / I feel stressed
I stop working and breathe (when,if) I feel stressed
I check my mistakes / I send the writing to my teacher.
I check my mistakes (then, before) I send the writing to my teacher.