Jawaban:

1. Tame animals: Horse, sheep, turtle, cow, camel, etc

Wild animals: Lion, tiger, hippopotamus, bear, cheetah, etc

2. My mother is buying an apple.

3. A shirt is cheaper than a trouser or a jacket.

4. Simple Past Tense: We studied English yesterday.

Progressive Past Tense: We were studying English yesterday.

Perfect Past Tense: We had studied English yesterday.

Penjelasan:

1. Tame animals are animals that doesn't have an excessive fear toward humans and they are seldom cause any harm to humans.

Wild animals are animals having an excessive fear and might cause harm toward human. They can be tamed by a specialist.

2. Present Continuous Tense/Progressive Present Tense

The tense is simply adding an auxiliary verb/to beand changing theverb into V-ing. The formula: Subject + to be + V-ing + Obj.

3. Comparative Sentence

Comparative sentence is a sentence that compares the adjective of two nouns. The formula is noun 1 + to be + adj-er + than + noun 2. There are adjectives that don't have the suffix -er such as expensive; therefore, we  use more to become ... more expensive than ...

4. Simple Past Tense

We simply remove the to be and change the verb into Verb 2/Past Verb. Formula: Subject + V2 + Obj.

Progressive Past Tense

We simply change the to be into past to be. The past form for are is were. Formula: Subject + past to be + V-ing + Obj.

Perfect Past Tense

We simply remove to be, add had, and change the V-ing to V3/Past Participle. Formula: Subject + Had + V3 + Obj.