Step 1: Understanding the sentences.
We are asked to fill in the blanks with the correct prepositions from the given options. Let's go through each sentence:
1. "She dived the swimming pool." The appropriate preposition here is "into," as we "dive into" something, like a pool.
2. "The boat sailed the lighthouse." The suitable preposition for this context is "past," as a boat sails past landmarks like a lighthouse.
3. "The treasure is buried the sand." The correct preposition is "beneath," as something is buried beneath the surface, such as sand.
Step 2: Analyzing the options.
- (A) in: This is incorrect for sentence 1, where "into" is more suitable.
- (B) onto: This is incorrect, as "onto" doesn't fit with the action of diving into a pool.
- (C) across: This doesn't work in sentence 2, as "past" is more appropriate for sailing near or around something.
- (D) past: Correct for sentence 2.
- (E) into: Correct for sentence 1.
- (F) beneath: Correct for sentence 3.
Step 3: Conclusion.
The correct sequence of prepositions is: \[ \boxed{E, D, F} \]
