having done做状语表示其动作发生在主句的动作之前。而doing往往表示和主句的动作同时发生。

(1) Having collected and evaluated the information, I help other scientists to predict where lava from the volcano will flow next and how fast. (U5B6 Reading-An exciting job)

(2) Having worked hard all day, I went to bed early. (U5B6 Reading-An exciting job)

(3) Having experienced quite a few earthquakes in Hawaii already, I didn’t take much notice. (U5B6 Reading-An exciting job)

(4) Having earlier collected special clothes from the observatory, we put them on before we went any closer.(U5B6 Reading-An exciting job)

(5) Having studied volcanoes now for many years, I am still amazed at their beauty as well as their potential to cause great damage. (U5B6 Reading-An exciting job)

(6) Having swallowed the fruit, the girl became pregnant and later gave birth to a handsome boy. (U5B6 Reading and writing-The lake of heaven)