Finding mistakes problem! (Designing and implementing successful incentive...)

[Thang77]

I am made confused with this sentence.Can you please help me to find out the mistake?
The sentence is:"designing and implementing successful incentive pay plans are a complex undertaking for any business"
And in these 2 sentence,I have found out the mistakes but I can't correct them.Please do me a favour!
No.1:"If you have no cash ,you can charge this dinner of your credit card."
No.2:"Each morning she waits at the bus stop in the corner for the downtownexpress bus"
In the first sentence,I think the word incorrect is "of".And in the second is "in".But I am not sure about my correction: of---with/on in---at/on.
Thank you very much in advance!

[Yankee]

Hi Thang

I would say the author of your first sentence wants you to change 'are' to 'is' (because 'designing and implementing' together is viewed as a/one complex undertaking).
- Designing and implementing successful incentive pay plans is a complex undertaking for any business.

1. I'd say you could use 'on' or 'with'.
2. I'd choose 'on'.
.

[SkiIucK]

[Thang77]

I think in the sentence"If you have no cash ,you can charge this dinner of your credit card." the word 'with' sounds better but It's my own view.
By the way,can you explain to me why you use this: - Designing and implementing successful incentive pay plans is a complex undertaking for any business.Yankee?
And SkiTuck,why you choose "off" instead of "of"?

[SkiIucK]

Hi,

As you can see, I haven't replaced 'of' with 'off'.