Both are completely grammatical and normal.
Both can be used.
The difference (as usual with past vs. perfect) is how you, the speaker, are choosing to relate the temporal structure of the events.
If you use the perfect "Have you heard", you are choosing to present the opportunity of hearing as something with present relevance. If you use "Did you hear",...
I think the simple idiomatic "on" might have started out as short for "on the schedule". At any rate, Merriam-Webster lists definition #4 of "on" (as an adjective) this way:
Their example is, "has nothing on for tonight"
So your sentence sounds fine in English:
"Is the class still on at 3?"
In writing, it looks a tiny bit tricky ...
Yes, your sentence is common, valid and clear, though occasionally that construction could be ambiguous. Where it is unclear, the sentence should be rewritten. Here are some similar examples.
"I bought a radio to play music." [I'm not making music, the radio is.]
"She sold brooms to sweep leaves." [She is not sweeping the leaves.]
"She sold brooms to ...
"Match" is acceptable in this context although the far more common verb in the U.S. is "check." Your sentence, however, is not highly idiomatic in other respects.
After solving the problems, match your answers with those in the answer key to ensure that your answers are correct
is pefectly acceptable, but much less frequent than would be
After solving ...
The key is whether the event can strictly be defined as temporal or whether it would best be defined as spatial.
I'm past the pizza shop.
describes the event temporally.
I've passed the pizza shop.
describes it spatially.
Left, in this context would imply you had already called in at the pizza shop a few minutes ago, but were now on your way home.
Yes, such a pattern is common and well-understood.
Even the literal phrase of:
My mom is out doing something.
works, meaning that your mom is currently not here but is doing something else (but you don't know/don't want to say what).
Wayne Goode gives you the traditional analysis.
A more contemporary analysis (Huddleston & Pullum, Cambridge Grammar of the English Language) treats out in these sentences as an intransitive preposition—that is, one which does not require an explicit object but constitutes a full-fledged preposition phrase by itself.
Note that ordinary ...
In these cases, if you use "out" by itself, "My dad is out", it is an adjective. If use "out" with a phrase after it as in these examples, it is an adverb. Dictionary.com
In the second example, because the verb "saw" has more than one meaning, if the sentence is shortened to "I saw her out", it can mean either "I saw her outside/away from home/etc." or "...
Well, most roads run in two directions, so, in many contexts, it wouldn't make a lot of sense to call it an uphill road (since it would also be a downhill road when going in the other direction). Instead, we might just say something like:
It's a hilly road.
The road has steep hills.
However, there may be times when describing an uphill road ...
The bold part of all of your examples is correct and idiomatic.
Note that we only use the word become when describing a change of state or degree, for example:
Your son will soon become a man - a change of state, from boy to man
Cars have become become more streamlined over the past 30 years - a comparison between how things were,and how they are now
"by themselves" here can also mean "on their own accord", which basically expresses something like honesty and discipline, or just "without being told by others to do it".
As a native speaker, I would say it like your friend did. You can also just get rid of "by", making it "they pay their fees in time themselves".
Typically, in common parlance, you would hear it as "change":
Can I change this for an orange juice, please?
The correct word is actually "exchange", and perhaps we could argue the correct way to write "change" when using it in this context would be:
I.e. We have remove the "ex" and replaced it with an apostrophe, acknowledging that it comes ...
It seems like you're mixing up two different idiomatic way of asking for a food order to be changed. "Change" means to alter something, while "exchange" means to swap, so they each have different uses.
We change something to something else.
We exchange something for something else.
Obviously, you cannot literally change one item of food or drink ...
This is correct usage of "as well as", but some parts of the sentence are a bit awkward.
You are using "just graduated from university" as an adjective, so it would need to be "just-graduated-from-university". Either way, it's awkward. Consider "I am a young, passionate developer who just graduated from university." In American English, it would be ...
Only the first option works in this case although, if the boy is alive, he would be rescued rather than retrieved. If he had died, his body might be retrieved. (So I shall use rescued rather than retrieved.)
The construction could not be rescued so far is another way of saying that so far the rescuers have not been able to rescue him.
The second ...
I think the advice you received means to pick one accent to learn and use yourself when speaking. The point of this is to simplify your learning. If you have to learn two different ways of saying everything then it will take you a lot longer to reach proficiency. There are many other places where English is spoken with other accents as well (Australia, ...
"Memory" is, by definition, a kind of "power", at least in the sense of "ability":
memory (n): The faculty by which the mind stores and remembers information.
"Memory power" is therefore redundant and not normally idiomatic:
He has a good memory for faces
If you want to use the word "power" then the "power of recollection" would be fine (often used ...