如图所示，电源电压U＝6V且保持不变，R₁＝10Ω，R₂是最大阻值为60Ω的滑动变阻器，L是标有“6V  0.72W"字样的灯泡，灯泡灯丝电阻不变．

（1）当R₂的滑片P到最左端时，要使灯泡L正常发光，S₁、S₂各应处于什么状态?
（2）当S₁、S₂都断开，5分钟内灯泡L消耗的电能是多少?
（3）调节滑动变阻器滑片，闭合S₁、S₂，当电流表示数最小时，整个电路消耗的电功率是多少?

1929～1933年资本主义世界经济危机爆发的导火线是（  ）

阅读理解

    Everybody should have some level of first aid ability, because accidents and medical emergencies can happen anywhere at any time. St John First Aid courses give you the knowledge and confidence to provide effective first aid whenever it's needed.

First Aid Level 1

    Ideal(理想的) for anyone who wants to learn basic first aid or needs to renew their first aid qualification. Courses can be held at St John or your workplace.

Fee: $162(includes GST)

Duration(持续时间): Eight hours

First Aid Level 2

    Includes all course content from First Aid Level One, plus an additional half day. Ideal for special first aiders, health and safety managers and anyone who needs a first aid qualification.

Fee: $235(includes GST)

Duration: 12 hours

Pre-Hospital Emergency Care (PHEC)

    Advanced training for first aiders who already hold unit standards 6400 and 6402. Ideal for people who require advanced first aid skills or a pre-hospital emergency care (PHEC) qualification for their work.

Fee: $635(includes GST)

Duration: Three days

Child First Aid

    Ideal for parents, grandparents and other family caregivers. A recognized qualification for childcare workers.

Fee: $65(includes GST)

Duration: Four hours

Outdoor First Aid

    First aid response for accidents and medical emergencies in the wilderness. For groups of eight or more.

Duration: One to two days depending on experience

Sports First Aid

    First aid response for common sporting injuries and medical emergencies. Includes ACC injury prevention advice.

Duration: Eight hours.