Spring Festival is the most important festival in China and an occasion ____ all family members get together, just like Christmas in the West.

Smiling is ________universal language and it is one of________ ways to express friendship.

Human beings are different from animals _______ they can use language as a tool to communicate.

Simon was _____ why many of his friends didn’t turn up at his birthday party.

With the development of modern industry, there will be ___ living space for wild animals.