双稳态电路中常用的触发方式有哪两种？
参考答案：稳态电路中常用的触发方式有：分别触发和计数触发两种
“a＞1且b＞2”是“a+b＞3”成立的（ ）
A．充分而不必要条件
B．必要而不充分条件
C．充分且必要条件
D．既不充分也不必要条件
Jade is the highest award in Chinese culture and medals are the most important prize in Olympics, so medals with jade is the perfect _________ to present the Olympics in Beijing.
A．connection
B．cooperation
C．combination
D．composition
