Meeting my uncle after so many years was an unforgettable moment, ______ I will always treasure.
Only if you work hard _____, because hard work is the ultimate source of success.
The _____ look on his face suggested that the teacher was quite _____ with the result.
______, I came to realize that my parents could not always stand by me.
In my opinion, more attention should be ______ the environment, which is of great importance.
I owe my success to Mr. Smith, a teacher from America, ______ help I have greatly improved my oral English.