These can be confusing. :)
Along with several other related meanings, one of the uses of can is to express ability. So, the weather has the ability to change very quickly in the mountains. Could is also used to express ability (also along with several other related uses), but in the sense of possibility or likelihood of happening.
So, if you say that the ...
In accordance with Systems and software engineering — Life cycle processes — Requirements
engineering ISO 29148:
It is important to agree in advance on the specific keywords and terms that signal the presence of a
requirement. A common approach is to stipulate the following.
— Requirements are mandatory binding provisions and use 'shall'.
— Non-requirements, ...
This is a difference in meaning, and in particular the meaning of "expensive".
Would you say "It is expensive" or "It was expensive"?
If by "expensive" you mean "the cost when you bought it" the this is a past fact you are talking about. Since it is in the past (and modal verbs don't have a past tense) you need to use the perfect "must have been". "It ...
All of them appear grammatical.
The first two, a and b, are acceptable as they are because "should do" and "ought to do" are adaptable to future events in this probabilistic sense.
The third and fourth, c and d, must be changed to "will have to do" to predict a future event, and then they are the same.
I think a and b are better expressions for the ...
The rule you were told is too simplistic. The example sentence is perfectly valid. Note that it doesn't explicitly say what it is that you will stop doing. Presumably the writer means that you will stop walking, and "walking" is a present continuous. But that word isn't actually in the sentence, it's just implied. Well, the word "walking" is in the sentence, ...
The "-ing" forms are used with a verb whose action is to be stopped. In your example sentence, the action that is stopped is not mentioned explicitly:
"stop walking", or "stop moving" or "stop driving", and you are to do that in order to "look". So the structure of this sentence is different.
When I was going to school is indeed the past continuous; it is not the same use of be going to.
As a substitute for will, you could say "When I get home from work, I'm going to start preparing my evening meal." "Tomorrow I'm going to play football."
Have + past participle => perfect (eg I have seen)
Be + present participle => continuous (eg I am wearing)
Put them together and you get
Have + past participle of be + present participle => perfect continuous (eg I have been wearing)
I have worn gloves usually means "On at least one occasion, not necessarily recently, I wore gloves" - the "present ...
"You could not make me happy, and I am convinced that I am the last woman in the world who would make you so."
Would links back to an earlier expressed or assumed if, such as if we got married
"You could not make me happy, and I am convinced that I am the last woman in the world who will make you so."
There's no link back to an earlier or assumed if. ...