Tenses Exercise For Classes 9 and 10
This grammar exercise tests your ability to use tenses correctly. It is designed for students of classes 8, 9 and 10.
Parents and teachers can print our worksheets for use in class or at home. You can find more tenses exercises and worksheets here.
English Grammar Exercises
Astronomers recently …………1……… (watched / watching / watch / have watched) a comet break into pieces, practically before their eyes. Their observations, ………2……. (reporting / have reported / reported / report) by scientists at Johns Hopkins University, …………3…….. (give / have given / had given) them surprising insight into the structure of these space objects.
Comets are fairly small (about 12 miles across or less) balls of ice, rock, and dust. They …………4……. (make / making / have made / had made) long, non-circular orbits around the sun. When a comet ………5…….. (came / come / comes / had come) close to the sun, the star’s heat ………6…….. (melt / melting / melts / melted) some of it, creating what looks like a tail. At this stage, it ……7………. (is looking / looks / looked) somewhat like a tadpole. Comets sometimes …………8……. (bursting / burst / bursted) into pieces when the sun’s heat ………9……. (turned / turn / turns / turning) their ice into water vapor.
Until a little ago, scientists ………10……… (think / thought / were thinking) that a comet’s center ………11………. (is / will / would) be different from its surface. That’s because comets probably ………12…… (formed / were forming / form / forms) at the same time as the solar system, so the material at the center has probably remained unchanged for just as long.
Solution
Astronomers recently watched (1) a comet break into pieces, practically before their eyes. Their observations, reported (2) by scientists at Johns Hopkins University, have given (3) them surprising insight into the structure of these space objects.
Comets are fairly small (about 12 miles across or less) balls of ice, rock, and dust. They make (4) long, non-circular orbits around the sun. When a comet comes (5) close to the sun, the star’s heat melts (6) some of it, creating what looks like a tail. At this stage, it looks (7) somewhat like a tadpole. Comets sometimes burst (8) into pieces when the sun’s heat turns (9) their ice into water vapor.
Until a little ago, scientists thought (10) that a comet’s center would (11) be different from its surface. That’s because comets probably formed (12) at the same time as the solar system, so the material at the center has probably remained unchanged for just as long.
