Final answer:
The conjunction 'and' fills the first blank to connect dual roles as singer and drummer, while 'but' goes in the second to show contrast. Verbs for the subsequent sentences cannot be selected without further context, and the comma review questions highlight varying sentence structures.
Step-by-step explanation:
In the first sentence, the most suitable conjunction is and because it connects the two roles that the person fulfills, being a singer as well as a drummer. Hence, the sentence should read, 'He is both a singer and a drummer.'
For the second sentence, the most fitting conjunction is but since it is used to show contrast between Ramu's financial status and his accomplishment. Therefore, the sentence would be, 'Ramu is poor but he managed to educate his son.'
Now addressing the prompts provided: When selecting the correct verbs for the sentences 'Under the table,' 'The choir usually,' 'Some of the actors,' 'Some of this song,' and 'Either my brother or my sisters,' we would need clear context to choose the appropriate verb forms. This context is currently missing from the exercise. For the review questions addressing commas in sentence structures, the examples provided show sentences that may need comma insertion or omission based on their structure and meaning.