Look at the pictures and say what they had done by four o'clock yesterday

Посмотрите на фотографии и скажите, что они сделали в четыре часа вчера

Natural disassuch as flood, fire, tornado, earthquake, tsunamis are becoming more and more frequent on our planet. In short description a natural disaster is a result of a natural hazard, which has a negative effect on human beings. These geologic processes can lead to serious consequences such as loss of life, property damage, economic problems. Certain areas are more exposed to natural disasters. For example, most of New Zealand’s coastline is exposed to tsunami hazard, while the Far East region is exposed to floods. Being aware of possible dangers, people should be prepared to protect themselves, their families and communities. Two important preparation steps are the developing of emergency plan and assembling a supply kit. However, all the known disasters have unique nature and should be approached separately. Some of the common natural hazards are as follows: earthquake, flood, drought, heat wave, hurricane, volcanic eruption, hailstorm, tornado, tsunami, landslide, wildfire, blizzard. I’d like to tell you a bit more about floods, hurricane and earthquakes. A flood is an overflow of water that submerges land. In severe cases it can result in human and animal deaths. Very often the crops are destroyed, which brings famine. A hurricane is a severe tropical cyclone or storm that often occurs in certain parts of the Atlantic and Pacific Oceans. This destructive hazard can lead to changes in weather and economy. It can also result in heavy rains, thunderstorm, flood or even tornado.

Is he watching TV now? - общий, образуется сменой порядка слов. Утвердительная форма будет: He is watching TV now.
Are you playing tennis or squash? - альтернативный, есть выбор и слово или (or).
What are you doing here? - специальный, есть вопросительное слово (what).
Who is dancing with Mike? - к подлежащему, вопросительное слово заменяет подлежащее, то есть ответ например будет: Kate is dancing with Mike.
You are doing your homework, aren't you? - разделительный, то есть вторая часть вопроса противопоставление первой На русский переводится: "не так ли?". Ты делаешь домашнюю работу, не так ли?
Надеюсь теперь будет понятнее