Can you help me with these English sentences and tenses?

Don’t open the box if the seal has been broken. Is basically the same meaning, either can be used in this case; has been or is.

The second sentence is more tricky. The sentence if you have enjoyed a good time is a little awkward. In English we would usually not put together enjoyed and good time, because it is redundant. We would say, if you enjoyed yourself at ABC, ring the bell. Or, if you had a good time at ABC, ring the bell. But, I caution you that if you are studying English with a teacher who also speaks English as a second language it is possible they are not aware of subtle difference. So, your two sentences would both be understood as the same, as you wrote them, but it is not how English speaking people would commonly phrase it.

We would not write your mentioned issue has been resolved this afternoon. Once you add when it was resolved then using the verb was is more appropriate. in fact your mentioned issue is odd as well. It should be the issue you mentioned was resolved this afternoon. What you wrote would be understood, but not commonly used. If you leave off the time it was finished you can use has. The issue you mentioned has been resolved, is correct also.

I am American, there might be subtle differences with British English possibly.

I thought I would add that you could write your aformentioned issue has been resolved. Again using has been you typically would not specify the time unless you put in a comma, or possibly a semi colon is better, I am not sure? Your aformentioned issue has been resolved; we fixed it at 1:00. But, more commonly people would use what I wrote above the issue you mentioned. I would say aformentioned is college level vocabulary probably? Most people talk and write for the masses on an 8th grade level from what I understand.

The only thing I have to add to @JLeslie‘s analysis is that the first and last sentences are not in passive voice. The word broken and resolved are used as adjectives. Switching to the “has been” form changes the sentences to passive voice. There is a subtle difference between the two forms of the sentence. The “is” form just talks about the current state while the “has been” form for these two sentences emphasizes some process that took place in the past. If you say “A seal is broken by cutting it with a knife” then this is also passive voice, since again the emphasis is placed on the action rather than the final state.

I would add to @JLeslie‘s answer that “If you have enjoyed a good time…” would be understood, but would indicate that you’re a non-native speaker. An English speaker would replace that phrase with either “If you have enjoyed yourself…” or “If you have enjoyed your stay…”

“Your aforementioned issue…” would be correct but is very formal. I would expect to see that in a business letter but not in speech or informal writing. Otherwise the sentence would more likely be replaced with “We have resolved your issue this afternoon.” or “The issue you mentioned was resolved this afternoon.”

While there are differences between British and American English, the examples @JLeslie gave are just as correct for British English too.

The present simple is used for talking about things which occur regularly or for states.

The present perfect implies a connection between a past event and a present state.

Therefore,

[ “It is broken” ] focuses on the present state of the object.

[ “It has been broken” ] shows that a past event is connected to the present in some way (it’s broken now, we didn’t know before, we want to use it now but can’t.)

The perfect aspect is actually rather simple, but it’s hard for non-native speakers to understand its usage because most other languages don’t employ perfects in the same way.

I am a native English speaker, and I also am very confused about this. I just cannot seem to wrap my mind about this. There is nothing SIMPLE or PERFECT about English.

@snowberry You do realize perfect is a verb tense. Past perfect, etc.

Yeah, I know, I know. And so is Simple a verb tense. But English ain’t perfect or simple. That’s my point. I teach English as a second language, and this is my nemesis. I just can’t seem to wrap my mind around it. I have a student with a degree in Arabic, and he’s all about verb tense. I keep telling him sooner or later he’s going to have to get a better teacher than me.

@snowberry – no language is. They’re complex, but not complicated.

English isn’t really a verb-dominated language anyway, tell your student to go learn some lexis instead – they’ll benefit from it more.

Well, English is a nightmare when it comes to spelling, that is for sure, and we have a bunch of words that have 3 or 4 meanings, some are spelled the same, some are spelled differently, but are the same verbally. But, as far as verb tense at least conjugating verbs is rather simplistic for most verbs; add an s, don’t add an s. I want, he wants, they want, we want. In Spanish you have to change the ending to agree with who you are talking about or you can have a big miscommunication.

Are these sentences correct or no? If no,where are the errors?
1.She told me that she is looking for the museum.
2.She asked when she can go home.

Both are correct. You could also say

She told me she is looking for the museum. (Omitting “that”)

I think it should be:

She told she was looking for the museum. Told is past tense so was should be past tense also.

She asked when she could go home.

But, I am no expert.