Bài 1: change these sentences into passive voice a, people make the artificial flowers of silk b, the people grow corns in many countries Bài 2: Fill in the blanks with the appropriate prepositions a, this picture is different... that picture b, I take part... outdoor activities of my school

Ex 1.

a. The artifical flowers are made of silk.

b. Corns are grown in many countries. 

Ex 2. 

a. from

b. in