写出下列词语的反义词。

延误——____         允许——____

已知函数$f\left(x\right)=\left\{\begin{array}{c}{e}^x,x\ge 0\\ -2x,x<0\end{array}\right.$则关于x的方程ff（x）+k=0，给出下列四个命题：

①存在实数k，使得方程恰有1个不同实根；

②存在实数k，使得方程恰有2个不同实根；

③存在实数k，使得方程恰有3个不同实根；

④存在实数k，使得方程恰有4个不同实根；

其中假命题的个数是（　　）

某同学在做研究弹簧的形变与外力的关系实验时，将一轻弹簧竖直悬挂让其自然下垂，测出其自然长度L₀；然后在其下部施加外力F，测出弹簧的总长度L，改变外力F的大小，测出几组数据，作出外力F与弹簧总长度L的关系图线如图所示．（本实验过程中未超出弹簧的弹性限度）．由图可知该弹簧的自然长度为____m；该弹簧的劲度系数为____N/m．（计算结果均保留两位有效数字）

阅读下面短文，掌握其大意，从每小题所给的A、B、C三个选项中选出最佳选项。

    One day Eric was traveling on horseback. At noon, he tied his horse to a 1. Afew minutes later, Paul came along and tied his horse to the same tree.

   “My horse is wild,” said Eric. “Please tie your horse to another tree, 2 my horse will kill yours.”

   “No way!” Paul said, “I shall tie my horse as I like!”He tied up his horse and had his 3 nearby. After a moment they heard a terrible noise. The two horses were 4. They ran up to them, but it was too 5. Paul's horse was killed. “See what your horse has done! You'll have to 6 it,”shouted Paul. And he brought Eric before Mr. Know.

    Mr. Know asked Eric some questions. But Eric said 7. At last Mr. Know said, “This man cannot speak.”

  “He can!” Paul said 8. “He talked to me when I met him.”

  “Are you 9?”asked Mr. Know. “What did he say?”

  “He told me not to tie my horse to the same tree because his horse was wild and would kill my horse.”

  “Oh,” said Mr. Know. “So he 10 you. Then can you expect to get money from him?” Paul had to leave silently.