Press "Ctrl + enter" while it doesn't print the result

Screen Link:
https://app.dataquest.io/m/349/project%3A-learn-and-install-jupyter-notebook/5/state

My Code:
def welcome(a_string):
print(‘Welcome to’ + a_string + ‘!’)

dq = ‘Dataquest’
jn = ‘Jupyter Notebook’
py = ‘Python’

welcome(dq)
welcome(jn)
welcome(py)

What I expected to happen:
Welcome to Dataquest!
Welcome to Jupyter Notebook!
Welcome to Python!

What actually happened:
nothing is printed

Hi @ipngasi ! Just a few questions to get a better idea why you’re having this problem:

  • Are you able to run the cell “manually” by either the toolbar or using the menu?
  • When you try to use the shortcut key, are you in command mode with the correct cell selected?
  • Do other shortcut keys work, for example, “SHIFT + ENTER?”

after I change to command mode then press “ctrl + enter”, it does work now!! and I notice I used ‘ instead of '. that’s why it causes the error. Thank you for your help!