题目

The Governor demanded that all the proposals _______ on May 1st.   A. must be submitted   B. be submitted  C. submitted  D. were submitted   答案：B如图是两个电阻串联的示意图．请在图中“等号”的右边画出两个电阻串联后的总电阻示意图，并在右边方框内用文字说明串联电路的总电阻大于各串联导体电阻的道理．