If you are telling someone something, you would use "how I can teach." If you are asking someone something or expressing frustration at a difficult situation, you would use "how can I teach" followed by appropriate punctuation.
Regarding this, how could or how can?
To summarize, 'can' is the present tense version of the word and 'could' is the past tense version of the word. 'Could' is also used when a condition must be fulfilled in order for the thing to happen. When asking someone to do something, either word can be used, but 'could' is considered to be more polite.
Subsequently, question is, will you or would you Which is correct?
Most of the times, the source of the confusion is the perception that “would” is always used as the past form of the auxiliary verb “will”. Yes, “would” is the past form of “will”, but it has various other uses too, which have nothing to do with the fact that would is the past form of “will”.
Could Can examples?
Can Could with Many Examples
|PAST ABILITY||He could run very fast when he was a child.|
|PAST REPEATED ACTIONS||I could run marathons when I was younger.|
|PAST SINGLE ACTION, STATIVE VERB||She could feel the wind on her face.|
|PAST SINGLE ACTION, ACTION VERB||NOT POSSIBLE!|
Would you or will you marry me?
"Will you marry me?" is a direct invitation. The speaker is asking about the will, the wishes, of the other person. "Would you marry me?" is less direct, and extra polite for this situation. It really means, "Would you marry me, if you should find me acceptable?"