3.The number of days in a week ... 7
is/are/was/were
4.English ... in many parts of the world
is spoken/were spoken/have spoken/speaks
5.... young have the future in their hands.
a/an/the/ko cs đáp án
6... Milk is good for you
a/an/the/ko cs đáp án
7.A tree ... in the garden yesterday
is planted/has been planted/is being planted/was planted