Are these sentences correct?
1.The lawyers asked for 2 more days to prepare for the case.
2.The lawyers asked for 2 more days to prepare the case.
"¢ The first sentence is not correct. You might say "The lawyers asked for 2 more days to prepare for the TRIAL." "Prepare" here means to get ready, to prepare themselves. "For" introduces another thing: the goal.
"¢ The second sentence is correct. The lawyers need two more days to prepare the case for the trial.
3.Mother is preparing for the birthday cake.
4.Mother is preparing the birthday cake.
"¢ Sentence 3 is not correct. Mother is preparing the birthday cake. She's preparing it for the party.
"¢ Sentence 4 is correct.
5.Mother is preparing dinner.
6.Mother is preparing for dinner
"¢ Sentence 5 is correct. Mother is getting dinner ready. She is making the meal itself.
"¢ Sentence 6 is also correct. In this case, "dinner" is an event. Mother is preparing herself/ the meal / the house for the occasion of dinner.
What is the difference between prepare and prepare for?
Here is part of the entry for "prepare" from the American Heritage Dictionary*
1. To make ready beforehand for a specific purpose, as for an event or occasion: The teacher prepared the students for the exams.
2. To put together or make by combining various elements or ingredients; manufacture or compound: prepared a meal; prepared the lecture.
3. To fit out; equip: prepared the ship for an arctic expedition.
*The American Heritage Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company 2003.