пожалуйста очень нужно прям срочно не как не пойму !!!! SOS

1 At that time engineers were applying scientific knowledge to design and develop machines.
2 They had forecast the behavior of this structure before the experiment began.
3 At 5 o'clock students will be playing basketball.
4 He hasn't passed his chemistry exam yet.
5 At present she is specializing in certain fields of engineering.