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 .