There __________ a big tree in front of my house . I could hear many birds sing in it .
—I havelearning math and I'm so worried. Could you help me? —Sure. I'd be glad to.
—I hear Mario never tells a lie. —That's right. He is anboy.
—is the population of your factory? —It has apopulation because it's a new factory.
—How long? —For two years.
—I saw Mr.Smith in the office at ten yesterday morning. —That's impossible. Hean Enghish party with us then.