Put the verbs in the brackets into the correct forms, help please

Question

1. Programming already (to become) a very important branch of national economy. 
For example, experts (to work) now on a computer program for agriculture. 
2. In the 1980s the production of microcomputers (to double), the production of 
microprocessors increased five times. This year we (to do) our best to meet 
requirements of the day. 
3. Our immediate task (to be) to advance our technology and increase the 
manufacture of computers. We certainly (to solve) this problem. 
4. The Elbrus 2 (to become) the next in the line of supercomputers. The engineers (to 
work) for three years before it was placed at the disposal of scientists. 
5. The first computers (to fill) a large room with their electronics. Air-conditioning 
was poor at that time and computers (to get) so hot during their work that the 
operators (to have) to dress in T-shirts and tennis shoes.

Дмитрий Елаков · Accepted Answer

1 - has become, work 
2 - doubled, have done 
3 - is, will solve 
4 - became, had been working 
5 - filled, got, had

Наталья Королева · Answer

1. Programming has already become a very important branch of national economy. For example, experts are working now on a computer program for agriculture. 
2. In the 1980s the production of microcomputers doubled, the production of 
microprocessors increased five times. This year we have done/have been doing our best to meet 
requirements of the day. 
3. Our immediate task is to advance our technology and increase the 
manufacture of computers. We'ii certainly solve this problem. 
4. The Elbrus 2 became the next in the line of supercomputers. The engineers had been working for three years before it was placed at the disposal of scientists. 
5. The first computers filled a large room with their electronics. Air-conditioning 
was poor at that time and computers were getting/got so hot during their work that the 
operators had to dress in T-shirts and tennis shoes.

Николай · Answer

1. has already become, are working 
2. doubled, have done 
3/is, will solve 
4. has become, had been working 
5/ filled, got, had to