can 'at' and 'by' both be used after 'amazed' having the same meaning?

[Twilit1988]

My sweetest and respected teachers,

1 : "Only a week later, he was sick" means 'he was sick last week' right?

2 : "I was amazed by his generosity" "I was amazed by his generosity"

can 'at' and 'by' both be used after 'amazed' having the same meaning???

3 : "Make the baby sit on the pushchair and amuse her by moving it around" correct?

4 : "Today i started using Yahoo! from 9 a.m. till 5 p.m." correct?

[JKidd]

1. No it means he was sick one week in the future of some reference point.

2. I assume one of them is supposed to be "I was amused at his generosity." This is not correct grammar. You can only use "by" here. "At" refers to a place or time.

3. yes, but the word "pushchair" is probably not the correct word.

4. should just be "today I used yahoo from 9am until 5pm" unless you say "today I started using yahoo at 9am and didn't sign off until 5pm."

[JKidd]

4. I should correct myself. I would not start a sentence with "Today...."

I would say "I used yahoo today from 9am until 5pm"

[AmYankee]

Hi Twilit

[Twilit1988]

Thanks AmYankee