It is obvious that this anti-smoking ____ is mainly aimed at young teenagers．

The two parties are holding the talk in a friendly________ at present. Hopefully，they will reach an agreement.

What British singer-songwriter Adele worried was ___________ the audience would accept her remained to be seen.

We’ll be free tomorrow, so I suggest ____ to the history museum. 

There is no _____ that the Chinese people will present to the world a successful, splendid  and unforgettable exposition（博览会）.