Answer:
If there [is] too much garbage, the air will be seriously polluted.
What a pity[,] I have to look at my little brother, so I can't go to the cinema tonight.
Explanation:
Any sentence with if at the beginning is usually present tense.
Commas always go after "What a pity".
I also did not see periods at the end of both sentences.
Answer:
I would say that it is D as my suggestion.
Answer:
to show that the land has been covered by floodwaters
'Feeling blue' means that a person is sad, or depressed.