How can I continue? The three long answers to this question cover the " continue" button, so I can't click on it to continue. I'm stuck!!!
If you're on something with a keyboard, try pressing Enter (Return) to continue.
This may not work if you had reported something or opened a sentence discussion, though, and the focus has moved; in which case, pressing Tab repeatedly until the focus is on the Continue button (it's after the three options in tabbing order, I think, and you should be able to see when each option is activated during tabbing) may then let you activate it with Enter.
I don't have an external keyboard. And my touchscreen keyboard won't come up on that page because there is no place to write.
About two weeks ago I mentioned here some problems of that course. (https://www.duolingo.com/comment/17140010)
Your "technical problem" is one of them - which is after all not a technical one but a problem of the developer, who wanted to be creative, but not in a useable sense.