There is a character encoding discontinuity between Google Docs/GMail and Pages. One approach is to select the text on the Google side, click and hold, and then drag and drop the text clipping into Pages. If that does not remedy the question boxes, then try the following AppleScript after you copy the Google side text to the clipboard, and before you paste into Pages:
use scripting additions
do shell script "/usr/bin/pbpaste -pboard general | /usr/bin/iconv -s -f LATIN1 -t UTF-16 | /usr/bin/pbcopy -pboard general"
Click on the Desktop, then press shift+cmd+U to open the Utilities folder. Double-click on Script Editor, choose New Document to your Desktop. Then copy the two lines of AppleScript above and paste into the Script Editor. Click the hammer icon (compile).
After you copy the Google side text to the clipboard, just click the Run button in Script Editor. There will be no output. In Pages, just paste and see if you are rid of the boxed question marks.