森林生态系统与草原生态系统相比较，森林生态系统（    ）

写出反义词。

对____     深____     光明____     安全____

进____     送____     公开____     困难____

如图所示为电流与电压的关系图像，由此可以判断（  ）

____ catch the first bus, she got up earlier that morning.

根据短文内容，选择最佳答案。    Several days ago, I went to my aunt's home and saw my cousin who is studying English linguistics in a university． He showed me his learning materials．Here are two pages of them.

Nice     Generally speaking, the word “nice” is quite an expression of praise. However, back in the late 12th century, if someone said you were “nice”, it was far from saying good words about you.     Very long ago, “nice” was used to mean “foolish” and “stupid”. That sounds more like the kind of words that would start a fight, not put a smile on someone's face. Later on in the 13th century, 'nice” came to mean “shy and nervous”. During the 14th century, it even meant “being careful”. But finally in the 18th century, it changed to the kinder meaning we know today, and ever since then, people have been using it in a lovable way.

Sad     All of us get sad from time to time. It's a usual part of life. A loved one passes away. We expect too much progress in an exam. Or the store is out of our favourite drink. These are all things that can make us sad.     However, once upon a time, “sad” had a very different meaning. Back in the 14th century, it was the perfect word if you had eaten too much food at dinner.     Through the years, the meaning of “sad” changed to “heavy” and then “tired”. Interestingly, when “sad” took on its present meaning, it was actually used instead of “unrot”, an old English word that was the opposite of “rot” that meant “cheerful” or “glad”.

    Now I know at some point in history, the meanings of some common words that we see every day meant something much different. The English language is developing all the time.