出售某种文具盒，若每个获利x元，一天可售出（6﹣x）个，则当x=（ ）元时，一天出售该种文具盒的总利润y最大．
3
根据句意及汉语提示完成句子
1. An electric _______(电击) can kill you.
2. I_______(打) the ball with the bat.
3. I'll be_______（高兴的）to help you.
4. The doctor told him to _________ (呼吸)in deeply.
5. The__________（数量）of money should be written both inwords and in figures.
8SF8400型照明灯灯具，当按下（）时，使8SK8555型低压馈电开关的绝缘监视器F427动作，进而切断照明灯220V交流电源，使照明灯熄灭。
A、照明灯盖的限位开关S1
B、信号按钮S2
C、紧急停车开关S3
D、故障检查开关S4
