Teacher: NORMALLY, students can't switch to other classes.
Student: You stress(ed) NORMALLY, does it mean there are abnormal situations?
If I were the student, should I say STRESS or STRESSED?
The event has happened recently, so I think the past tense is not that justified. But I am not sure....
Is your 'introduce discussion' reason able for account for the use of SAY like this?
"He was running, —running desperately, running for his life, running until he burst his heart and fell dead upon his face."
"Running from what?"
"There lies our problem. There are indications that the man was crazed with fear before ever he began to run."
"How can you say that?"
When a man utters 'how can you say that', the THAT must be something past, then why not SAID?
COULD here is the usual past form of CAN;
in modern English, to refer to the present, we can use CAN/COULD; to the past, only COULD is possible, when the meaning is ABLE/IN A POSITION TO DO STH; in that conversation, the speaker is referring to a particular thing said in the PAST, so I am not able to use grammar to explain it, though I think it's natural....
could (kd) KEY
Past tense of can1
Used to indicate ability or permission in the past: I could run faster then. Only men could go to the club in those days.
Used with hypothetical or conditional force: If we could help, we would.
Used to indicate tentativeness or politeness: I could be wrong. Could you come over here?
past of can
—used in auxiliary function in the past <we found we could go>, in the past conditional <we said we would go if we could>, and as an alternative to can suggesting less force or certainty or as a polite form in the present <if you could come we would be pleased>