Fill in the blanks with the proper forms of given words.
I helped my mother to buy some beef and three ______(potato) for supper today.
"Belt and Road"（一带一路) are the two wings of developing Asia in the ____(twenty-one) century.
Please keep ___(silence) in the concert hall because people are enjoying Lang Lang's piano performance.
Candy _________(lay) out the tea, fruit and snacks on the table and waited for the visitors.
With the development of technology, mobile phones are _______(wide) used these days.