搜题请搜索小程序“爱下问搜题”
问题 单项选择题

海豚生在海里，但海豚不是鱼，那么下列论述正确的是：

A．鱼不是生活在海里

B．生活在海里的不一定是鱼

C．不是海豚的动物是鱼

D．不是海豚的动物都不是鱼

答案

参考答案：B

单项选择题

As viewed from space, the Earth’’s distinguishing characteristics are its blue waters and white clouds. Enveloped by an ocean of air consisting of 78% nitrogen and 21% oxygen, the planet is the only one in our solar system known to harbor life. Circling the Sun at an average distance of 149 million km (93 million miles), the Earth is the third planet from the Sun and the fifth largest planet in the solar system. Its rapid spin and molten nickel-iron core give rise to an extensive magnetic field which, coupled with the atmosphere, shields us from nearly all of the harmful radiation coming from the Sun and other stars. Most meteors burn up in the Earth’’s atmosphere before they can strike the surface. The planet’’s active geological processes have left no evidence of the ancient pelting it almost certainly received soon after it was formed. The Earth has a single natural satellite — the Moon.

Approximately how much of the Earth’s atmosphere is nitrogen

A．One-fourth.

B．One-half.

C．Three-fourths.

D．All of it.
查看答案
选择题

“易大传：‘天下一致而百虑，同归而殊途。’夫阴阳、儒、墨、名、法、道德，此务为治者也，直所从言之异路，有省不省耳。”这段话反映的历史时期是[ ]

A．西周

B．春秋战国

C．秦朝

D．明朝
查看答案