_______ seems strange to us is ________ the clever boy failed in the exam.
You should make it a rule to leave things _______ you can find them again.
When you read the book, you’d better make a mark _____ you have any questions.
You should let your children play ______ you can see them.
Now he works in the factory ______ his father used to work.
The visitor asked to have his picture taken _______ stood the famous tower.