Does two-factor authentication prevent access when encrypted database is stolen?

If you store your encrypted passwords on the cloud (e.g. as a file on Dropbox or on LastPass servers, etc.) does having two-factor authentication enabled (for Dropbox or your LastPast account, etc.) protect you if hackers steal your encrypted file of passwords from Dropbox or LastPast (etc.) and manage to decode your master password for the file (because, say, your password was a weak one, like "12345")?

 

...And in a related question: what makes a strong password? For instance, is this a strong password: "youaretheappleofmyeye"? Or does a password have to look random, like "TP$w08K90lAaw!R," to be strong?

I ask, because if I type in "youaretheappleofmyeye" to any of the password strength estimators that I've linked to below, they all say it's great, but the advice I get about making a strong password is to use numbers, symbols, upper and lower case, and no dictionary words. So, what's going on here/what am I not understanding?

• https://howsecureismypassword.net/
• https://passfault.appspot.com/password_strength.html
• https://www.grc.com/haystack.htm