Mr. Klein told the class that a new student, Inez, would join them soon. He 1 that Inez was deaf. She “talked” with others by using sign language. Mr. Klein knew sign language, and he decided to teach 2 students so that they could also “talk” with Inez.
    First, they learned to sign the letters. Some letters were hard to3 . Other letters, such as C ,were easier because the shape of the hand was the same as the shape of the letter.
    The 4 thing they learned was finer spelling. They signed one letter after another to spell a word. They5with two-letter words such as at and on . Then they spelled 6words.
    Finally, Mr. Klein showed that 7 one sign could be used for a whole word. To make the sign for the word fine, a person spreads out the fingers on one hand, 8 the thumb(拇指) to the chest(前胸) , and moves the hand away from the chest. Signing is not just done with the hands. Expressions on the face are also9  . The students learned to sign a question mark by using expressions on the face.
When Inez first entered the classroom. She looked  10 . But the students signed, “Good morning, Inez. ” She gave the class a big smile and signed back, “What a wonderful welcome !”

如图甲所示，在空间存在一个变化的电场和一个变化的磁场，电场的方向水平向右（图甲中由B到C），场强大小随时间变化情况如图乙所示；磁感应强度方向垂直于纸面、大小随时间变化情况如图丙所示。在t=1s时，从A点沿AB方向（垂直于BC）以初速度v₀射出第一个粒子，并在此之后，每隔2s有一个相同的粒子沿AB方向均以初速度v₀射出，并恰好均能击中C点，若AB=BC=L，且粒子由A运动到C的运动时间小于1s。不计重力和空气阻力，对于各粒子由A运动到C的过程中，以下说法正确的是

①互相尊重，自尊自爱

②既要放开自己，又要掌握分寸

③心底无私天地宽，不需要考虑交往的方式、场合和时间

④既要热情主动，又要注意交往的方式、场合和时间等因素。