Prefixes and suffixes word formation: English ESL worksheets pdf & doc - Free Printable

Here is the step-by-step solution to the worksheet.

Analysis of the Task:
The goal is to fill in the blanks with the correct prefix from the list: il-, ir-, im-, in-, un-, dis-.
These prefixes are used to make words mean the opposite (negate them).

Step-by-Step Solutions:

1. Sentence: "Selling soft drugs in our country is ....legal."
* Word: Legal.
* Context: Selling drugs is against the law.
* Prefix: The opposite of legal is il-.
* Answer: illegal

2. Sentence: "My brother is a very ....organised person and his room is always a complete mess."
* Word: Organised.
* Context: His room is a mess, meaning he is not organized.
* Prefix: The opposite of organized is un-.
* Answer: unorganised

3. Sentence: "Don’t you think it was really ...responsible to leave me there alone?"
* Word: Responsible.
* Context: Leaving someone alone is not a responsible thing to do.
* Prefix: The opposite of responsible is ir-.
* Answer: irresponsible

4. Sentence: "It’s ... possible to meet all their requirements. They seem to be always ....satisfied."
* Word 1: Possible.
* Context: Meeting *all* requirements is hard or impossible.
* Prefix: The opposite of possible is im-.
* Word 2: Satisfied.
* Context: They are always wanting more.
* Prefix: The opposite of satisfied is dis-.
* Answer: impossible, dissatisfied

5. Sentence: "My mother can be very ...tolerant of people who have lots of piercings and tattoos."
* Word: Tolerant.
* Context: This implies she doesn't like or accept them.
* Prefix: The opposite of tolerant is in-.
* Answer: intolerant

6. Sentence: "I don’t understand your way of thinking. For me it’s completely ...rational."
* Word: Rational.
* Context: If you don't understand the thinking, it seems crazy or not logical.
* Prefix: The opposite of rational is ir-.
* Answer: irrational

7. Sentence: "That’s totally ...believable. We’ve won the first prize."
* Word: Believable.
* Context: Winning first prize is amazing and hard to believe.
* Prefix: The opposite of believable is un-.
* Answer: unbelievable

8. Sentence: "I’m afraid his handwriting is ...legible."
* Word: Legible.
* Context: "I'm afraid" suggests a negative quality, meaning you can't read it.
* Prefix: The opposite of legible is il-.
* Answer: illegible

9. Sentence: "You look a bit ...happy. What’s the matter?"
* Word: Happy.
* Context: Asking "What's the matter" implies the person is sad.
* Prefix: The opposite of happy is un-.
* Answer: unhappy

10. Sentence: "We’ve got a long list of ...regular verbs to memorise by next Monday."
* Word: Regular.
* Context: In grammar, there are regular and irregular verbs.
* Prefix: The opposite of regular is ir-.
* Answer: irregular

11. Sentence: "Don’t buy ...practical presents. It’s a waste of money."
* Word: Practical.
* Context: A waste of money suggests the item is not useful.
* Prefix: The opposite of practical is im-.
* Answer: impractical

12. Sentence: "Avoid fast food. It’s very ...healthy."
* Word: Healthy.
* Context: Fast food is generally bad for you.
* Prefix: The opposite of healthy is un-.
* Answer: unhealthy

13. Sentence: "That was highly ...respectful behaviour. Don’t you think?"
* Word: Respectful.
* Context: The word "highly" emphasizes the behavior, which is implied to be bad here.
* Prefix: The opposite of respectful is dis-.
* Answer: disrespectful

14. Sentence: "...loyal people are the ones you should stay away from."
* Word: Loyal.
* Context: You should stay away from them, so they must not be faithful.
* Prefix: The opposite of loyal is dis-.
* Answer: disloyal

15. Sentence: "My trip to Thailand was an ...forgettable experience."
* Word: Forgettable.
* Context: Usually, people talk about trips that are memorable (hard to forget).
* Prefix: The opposite of forgettable is un-.
* Answer: unforgettable

16. Sentence: "Her parents ...approve of the boy Katie has started dating. And you know what? I don’t blame them."
* Word: Approve.
* Context: The speaker says "I don't blame them," implying the parents have a negative opinion of the boy.
* Prefix: The opposite of approve is dis-.
* Answer: disapprove

17. Sentence: "Do you ever feel ...secure in front of a big group of ...familiar faces?"
* Word 1: Secure.
* Context: Being in front of a big group can make you feel nervous or unsafe.
* Prefix: The opposite of secure is in-.
* Word 2: Familiar.
* Context: "Big group" usually implies strangers.
* Prefix: The opposite of familiar is un-.
* Answer: insecure, unfamiliar

18. Sentence: "Tanya is such an ...decisive girl. Whatever you ask her for she has difficulty making up her mind."
* Word: Decisive.
* Context: She has difficulty making up her mind, which means she is not decisive.
* Prefix: The opposite of decisive is un-.
* Answer: indecisive (Note: While 'un' is the standard prefix for decisive, 'indecisive' is also very commonly used and fits the context perfectly).

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Final Answer:
1. illegal
2. unorganised
3. irresponsible
4. impossible, dissatisfied
5. intolerant
6. irrational
7. unbelievable
8. illegible
9. unhappy
10. irregular
11. impractical
12. unhealthy
13. disrespectful
14. disloyal
15. unforgettable
16. disapprove
17. insecure, unfamiliar
18. indecisive