Put the verbs in brackets in the correct tense form:

11When winter(come), I (skate) in the yard.

12If you(continue) to act like that, your mother(punish) you.

13If she(not/stop), she (regret) it.

14Before he (go) home, I (tell) him the truth.

15Yesterday Bob(not/visit) his granny because he (be) busy.

16Yesterday at 6 o’clock I (speak) to Betty on the phone.

17 When she (give) back my book, I(bring) it to you.

18 I (help) him if he (ask).

19 Tomorrow I (visit) you if you (be) at home.

20 If we (meet), I(give) you her address.

Archaeological zone of Chan Chan, Peru
The list of" endangered " UNESCO sites included Chan Chan-Chimu cultural center and the largest city of pre-Columbian era in the world. According to the official version, it originated around 1300. In the period of greatest prosperity, the population of Chan Chan was about 60 thousand people! The city was divided into 9 Autonomous districts, with its own temples, houses of ordinary people and palaces.
However, now you can see only the remains of religious buildings and residences. Torrential rains, floods and storms destroy the unique mud-brick city. More dangerous than an earthquake. Scientists fear that strong tremors Chan-Chan just can not stand.

Объяснение:

1. Because it was very difficult to build tall skyscrapers at that time and it was dangerous,it was difficult to get the necessary funds to build a skyscraper.

2. They can start building skyscrapers when they are sure that they have the right materials and the land is suitable for building a tall building.

3. When the Elevator was invented, people's lives became noticeably easier.And people were able to build taller skyscrapers.

4. Because it would be inconvenient to build them outside the city, especially since when building a skyscraper in the city there may be offices,shops,apartments, etc.

5. Because these buildings are built "to the sky".

6. It was built over two years, from 1929 to 1931.

7. Here you can find various cafes, shops, supermarkets and apartments, as well as much more.