posted by rfvv on .
1. We will lead your children to the joys of reading.
2. We will lead your children to the joy of reading.
3. We will lead your children to joy of reading.
(Which expressions are grammatical? Are both acceptable?)
4. I learn many things in class from her kind teaching.
5. I learn many things at class from her kind teaching.
(What is the difference between 'in class' and 'at class'?)
6. Dinosaurs lived on the earth long ago.
7. Dinosaurs lived on earth long ago.
(Which one is right, 'on the earth' or 'on earth'? Are both OK?)
1 and 2 are fine; 3 is not.
4 is fine; 5 is not. The word "in" means "inside," in a way, and is just the correct one to use. It's idiomatic, I guess; there's no real explanation!
6 and 7 are both correct.
Just a little extra on the word "at" as a preposition. It is usually a "function" word such as:
1. 1 - used as a function word to indicate presence or occurrence in, on, or near - staying ∼ a hotel - ∼ a party - sick ∼ heart
2. 2 - used as a function word to indicate the goal of an indicated or implied action or motion - aim ∼ the target - creditors are ∼ him again
3. 3 - used as a function word to indicate that with which one is occupied or employed - ∼ work - ∼ the controls - good ∼ chess
4. 4 - used as a function word to indicate situation in an active or passive state or condition - ∼ liberty - ∼ rest
5. 5 - used as a function word to indicate the means, cause, or manner - sold ∼ auction - laughed ∼ my joke - act ∼ your own discretion
6 a. 6 a - used as a function word to indicate the rate, degree, or position in a scale or series - the temperature ∼ 90 - ∼ firstb. b - used as a function word to indicate age or position in time - will retire ∼ 65