Sentence 1: When you write an essay, you need a strong thesis.
write : tense present; aspect simple, mood indicative .
need: tense present, aspect simple, mood indicative.
Sentence 2: Although the task was difficult , he kept trying , and he eventually succeeded .
was: tense past, aspect simple, mood indicative.
kept trying : tense past, aspect continuous , mood: indicative .
succeeded : tense past, aspect continuous , mood indicative.