Do you know how many people are there in her family?

• Mistake: "are there" should be "there are".
• Correct sentence: "Do you know how many people there are in her family?"
• Answer: B (the mistake is in part B)

It’s ten o’clock. My father unloads the vegetables.

• Mistake: The present tense "unloads" is incorrect here because the sentence describes a current activity happening at that moment.
• Correct sentence: "It’s ten o’clock. My father is unloading the vegetables."
• Answer: B (the mistake is in part B)

My class has a picnic two a year.

• Mistake: "two a year" is incorrect; it should be "twice a year" or "two times a year".
• Correct sentence: "My class has a picnic twice a year."
• Answer: C (the mistake is in part C)

My mother needs to buy a bottle of cooking oil and five hundred gram of beef.

• Mistake: "gram" should be "grams" because "five hundred" refers to a countable quantity, so we need the plural form.
• Correct sentence: "My mother needs to buy a bottle of cooking oil and five hundred grams of beef."
• Answer: D (the mistake is in part D)

My brother has a lot of homeworks to do this evening.

• Mistake: "homeworks" should be "homework" because "homework" is an uncountable noun and does not take the plural form.
• Correct sentence: "My brother has a lot of homework to do this evening."
• Answer: C (the mistake is in part C)

But the verbs in brackets into the correct form or tense and write your answer.

• Mistake: The sentence is incomplete or incorrectly phrased. It should be: "Put the verbs in brackets into the correct form or tense and write your answer."
• Correct sentence: "Put the verbs in brackets into the correct form or tense and write your answer."
• Answer: A (the mistake is in part A)