Basic Tokenizer Question on String Errors [Problem 281]

Hello y'all,

I'm working through basic tokenizer (Problem #281), and I'm able to solve all the test cases save for these two:

1. REM here's a break
2. REM Just a fine comment!

These lines are supposed to result in an error, but I'm unable to see where the error is.

Here's my current thought proccess:

1. For case 1, strings are supposed to open with double quotes, thus the single quote in here's shouldn't break anything.
2. For case 2, the only thing I can think of is the exclamation point at the end of the line. Is this illegal?

Any help would be appreciated!