The key _________ the string was put into the door to stop the kite _________.
To understand the grammar of the sentence, you must break it into parts.
We went to Canada to travel and my cousin ______ as our guide.
If you think that treating a woman well means always her permission for things, think again.
Someone who lacks staying power and perseverance is unlikely to ___ a good researcher.
Don’t respond to any e-mails ______ personal information, no matter how official they look.