Answer:
11. D
14. C
Step-by-step explanation:
Context helps the reader get a better background of the idea, since lots of ideas are open to interpretation. Providing context will help narrow the reader's interpretation of the content down so it's easier to understand where the passage is coming from.
A dictionary will best help you differentiate words that may be similar, since they provide you with the defintion of them.
Using an antonym or a spell-checker is super ineffective since they are used for different reasons.