被动语态的基本用法 — 英语填空题
题目
根据句意，用所给动词的被动语态填空（每空一词，注意时态）。Paper (1)___ (invent) in China over two thousand years ago, and today it (2)___ (use) in every corner of the world. The light bulb, which (3)___ (improve) by Thomas Edison in 1879, is still regarded as one of the most useful inventions ever.