Answer:The correct sentences are:
1. She has thrown it away.
2. He spat on the floor.
3. Have you got it right?
4. Has he been eating the food?
Explanation: The correct sentences have a change of tense to participle in them. A participle is a word that is used in place of a verb to denote an adjective or a noun. For example:
If we look at the first sentence, the past participle of throw is not used instead the past tense is used. A throw is the action done in the past and hence the past participle of throw would be 'thrown' and not the incorrectly used word 'threw'.
If we look at the second sentence, the past tense of spit is incorrect. Spit is the action verb and the past tense is spat not spitted. So 'spat' is correct.
If we look at the third sentence, the sentence used the verb 'get' but in the context of the sentence and the use of the word 'have' we see that it indicated it to be past tense. So the correct word would be got and not get.
If we look at the fourth sentence, the sentence has a missing word for the whole sentence to be complete. The use of the indicator word 'has' shows that it is in the past continuous tense. So the word 'been' should be added before 'eating' to make it correct.