Although I have made a lot of new friends, Nancy remains my best friend.
A：is still
B：is often
C：is never
D：is seldom
R1与R2并联在电路中，消耗的功率之比为4：3，如果把R1、R2串联起来，仍接在同一电路中，则R1、R2消耗的功率之比是（ ）
提出问题：这种黑色不溶物是什么呢？
猜想与假设：这种黑色不溶物中可能含碳。
His friends ______ at him two days ago.（ ）
