I would like to check how native speakers will answer the following exam questions:
1- Oh, no! That _____ be the time! I am so late.
Here I was asked to choose between "might, must, can't". Which one is correct and which one is wrong and why?
2- You look happy! You _______ have received some good news!
Here I had to choose between "must, could and can't". I chose "must", but I am not sure whether it is the correct answer. Could you tell me if my choice was correct or wrong?
In the same exam, I was asked another confusing question.
2- You look very thin! ____ you_____ well lately?
I had to choose between the following:
a. Haven't ... felt b. Didn't...feel c. Haven't... been feeling
To be honest, both a and c made sense to me! It was confusing. Which one would be chosen by a native speaker of English?
In the same English exam, I have been asked to choose between "so and so that" to fill in the blank in the following sentence:
I am studying hard _____ I can do well in my exams!
This was confusing too because the answer here should be 'so that', but I know that every occurrence of 'so that' can be replaced with 'so' without losing meanings, but not vice versa. Is that true?