1. He had to check the oven every 15 minutes.
2. He had to check the oven every 15th minute.
(Are both grammatical?)
3. Mom will give me turkey sandwich for lunch for the next two week.
(Is 'for lunch' an adjective pharase or an adverbial phrase? Does 'for lunch' modify 'turkey sandwiches' or 'gave'?)
1. is correct. 2. is not used.
3. "For lunch" is an adverbial phrase modifying "will give."
1. Both sentences are grammatically correct, but they have slightly different meanings.
In the first sentence, "He had to check the oven every 15 minutes," it implies that he needs to check the oven repeatedly, with each interval being 15 minutes. This means he could check the oven more than once within a 15-minute period.
In the second sentence, "He had to check the oven every 15th minute," it implies that he needs to check the oven only once every 15 minutes. This means he would check the oven at the exact moment when the 15th minute of each hour arrives.
2. The correct phrasing would be "He had to check the oven every 15 minutes."
3. "For lunch" is an adverbial phrase in this sentence. It modifies the verb "give."
To clarify, "Mom will give me turkey sandwiches for lunch for the next two weeks." The phrase "for lunch" tells us the purpose or when the turkey sandwiches will be given. It specifies that the sandwiches are intended for lunchtime.