It’s ____ knowledge that the Nile is thelongest river in the world.

—Who should be responsible for the accident—The boss, not the workers. They just carry the orders _______.

Do you know Uncle Tom is crazy about gardening?—Sure. He ____ his flowers in the garden now.

．—Has your father finishedhis report—Sorry，I don’t know．He ________ it this morning．

So you know Catherine?—Yes, it was last week_____ she came to visit my roommate Jane.