[ Comma ]
There is no reason to feel sad so try to smile.
A. There is no reason to feel sad so, try to smile.
B. There is no reason, to feel sad so try to smile.
C. There is no reason to feel sad, so try to smile.
D. No commas needed.

Random Topics:
Prepositions and Phrasal VerbsGerund or to InfinitivePassive Voice and Relative ClausesHow often - long - much - manyPast ModalsNounsGerund, Participle, Infinitive, or AppositiveConditional TensesThird ConditionalBe Going To vs. WillOther quiz:
Grammar & Vocabulary › ViewAnd, of course, social media is a great way to reconnect with old friends and ___.
A. catch up
B. reconnect
C. stick together
Tenses › View
. Identify the tense: ‘I will be traveling to New York next week.’
A. Present perfect tense
B. Past simple tense
C. Future continuous tense
D. Present continuous tense
Tenses › View‘Where is Kate?’ ‘She (watch) TV in the living room.’
A. watches
B. doesn’t watch
C. is watching
D. watch
Future Tenses › View
Oh, somebody is knocking! I … open it.
A. are going to
B. am going to
C. will
D. is going to
