Heads from different countries gathered in Amsterdam and President Xi jinping _____ a speech on nuclear safety.

I ________ in London for many years，but I've never regretted my final decision to move back to China.

The little boy _____on the mat ____ to his parents that blackbirds had _____their eggs on Mars．

Some passengers were ______ in the traffic accident and taken to the nearest hospital.

People wrote letters to get in touch in the past. Nowadays email has       the way people communicate.