单项选择题
A.several times throughout the year B.during spring and fall C.during the summer D.as seldom as possible
A.all nature, including man, is growing then B.it lasts longer than the other seasons C.it is not too warm and not too cold D.both B and C
A.stays the same throughout the year B.varies from day to day C.changes with the seasons D.changes from year to year