Ответ:

1. The advantages of the high-speed ground transport are ( Present Simple Active Voice; to be- инфинитив) obvious. Преимущества высокоскоростного, наземного транспорта очевидны.

The advantages of the high-speed ground transport aren’t obvious.

2. Steel replaced ( Past Simple Active Voice ; to replace — инфинитив ) iron everywhere in the rail construction. Сталь везде заменила железо в конструировании/сооружении рельс.

Steel didn’t replace iron everywhere in the rail construction .