光电耦合器要求输出功率大时应选用（）
A.光敏三极管
B.达林顿管
C.IC光耦合器
D.光敏二极管
参考答案：B
“__________?” “He is smart and helpful.”
A．What does he look
B．What is he look
C．What is he like
D．What does he like
油品中石蜡组分含量越多，其凝固点越高。
