The ancient phenomenon consisting in
alteration of vowels in the root, suffix
or ending depending on the grammaticale
form or meaning of the word is called
Amlaut
Ablaut, Umlaut
verner s law
Umlaut, verner's law.​

1. drink; will get
2. won't be late; gets
3. go
4. is; will have
5. wear; will look
6. buys; will wear
7. comes; comes; will phone
В данном упражнении большинство предложений в First Conditional (1 тип условного наклонения). Исходя из правила, можно легко выполнить это упражнение. If + Present Simple, Future Simple (will) (или эти части могут поменяться местами). 
Также присутствуют предложения с придаточными времени (when). После слов when, as soon as, until, after, before никогда не ставится Future Simple (will), а идет глагол в Present Simple

There is more water than land on our planet. The largest and deepest ocean in ..the. world is .the.Pacific, then comes ..the. Atlantic. ..the. Indian ocean is only .a. little smaller. .the.. smallest ocean is ..the. Arcticthe longest river in .the.. USA is ..the. Mississippi, ..the. largest sea is ..the. Mediterranean, ...the deepest lake is ... Lake Baikal. Large masses of ... land are called ... continents. They are ... Europe and Asia, ... North and ... South America, ... Australia and ... Antarctica. There are mountain chains in many parts of ...the world. Some of them such as ..the. Urals are old, others like ..the. Caucasus are much younger. ..the. highest mountain chain, which is called ...the Himalayas, is situated in Asia.