Поставьте глагол в скобках в соответствующее время группы indefinite или perfect.
1. the alkaloid of opium (to constitute) about 25% by weight.
2. the attention to natural sources of drugs (to increase) at present.
3. since ancient times man (to use) different parts of plants for medicinal purposes.
4. by the time of harvesting the amount of active constituents (to become) the highest.
5. botanists (to collect) the leaves of this plant before the maturing of fruits and seeds.
6. since the war the institute of medicinal and aromatic plants in moscow (to develop) and (to bring into use) some 60 medicinal preparations.
7. the specialists recommend a clinical use of the drug as it already (to pass) necessary laboratory investigations.
8. we studied the methods of storing new medicinal herbs after we (to carry on) their cultivation.

Жили-были старик и старуха,его жена. У них не было детей.
У старика было домашнее животное -- птичка. Маленькая серая птичка. Старик нежно любил её. Он заботился о ней. Каждое утро и вечер он кормил и поил её. Однажды старик отправился в магазин,дабы купить еды. Своей жене он сказал:"Я иду в магазин,чтобы купить хлеба,соли,масла,спагетти и сахара. Позаботься о моей птичке! Корми и пои её утром и вечером!" "Хоршо",сказала жена."Я всё сделаю". Было очень холодно. Старик надел тёплые брюки и ботинки,свитер,пальто,тёплую шапку и ушёл. 

When I was at the festival, it was such a good and sunny day. It seemed like everything should have been okay, but, unfortunately, we had got a "trouble". 
This morning, I just woke up and started thinking about this event. It was the Day of our city. I was invited to the centre of the city, for my friends knew that I liked the things like going to the festivals. This one has been organized by a company. 
When I came there, everything had already been prepared. The centre of our city had been decorated with many things which surprised me much. Some my friends rang me up, because I didn't see them anywhere. Later, I realized that I had not been attentive. Though, I should admit there was very crowdy. Anyway, we've met. They said they had never found their city as such a nice one. Frankly, I was by their side. 
So, as I said before, everything had been okay until... So, some time went by, and it started to rain. None expected it could rain that day. Anyways, it didn't make us unhappy. We've seen a great concert, thus everyone was satisfied.