Во сколько раз снижаются потери электроэнергии на нагревание проводов при повышении напряжения в ЛЭП в четыре раза?

2.what did you visit
3.when didyou arrive
4.how did you travel
5.why did you hire a car
6.what did yiu discuss
7.whe did you arrive back
8.what time did you start work this morning at или 
when did you start work this morning
9.what time did you telephone Hans Kinger at
10.when did he sign the contract