1.They decided (sell) their old house and buy a bigger one. 2.Sam really enjoyed (watch) the play last night. 3.My sister let us (use) her flat for the party. 4.I look forward to (hear) from you soon. 5.We stopped (read) when the bell rang. 6.She forgot (pay) the phone bill. 7.I remember (give) you the key before I left. 8.My mother made me (clean) the window. 9.Anna forgot (take) out the rubbish last night. 10.Sara said she would (order) a pizza for dinner.1.They decided (sell) their old house and buy a bigger one.

1. They decided to sell their old house and buy a bigger one.
Explanation: In this sentence, "decided" is the main verb indicating an action that someone decided to take. The infinitive "(to) sell" is used after the verb "decided" to show what action they decided to take. The infinitive "(to) buy" is also used to show the action they decided to take. The word "their" shows that they are talking about their own house.

2. Sam really enjoyed watching the play last night.
Explanation: In this sentence, "enjoyed" is the main verb indicating a past action that Sam experienced. The -ing form of the verb "watch" is used after the verb "enjoyed" to show what action Sam enjoyed. The word "the" indicates that Sam is talking about a specific play that he watched. The word "last night" indicates the time when Sam watched the play.

3. My sister let us use her flat for the party.
Explanation: In this sentence, "let" is the main verb indicating an action of giving permission. The object pronoun "us" shows that the speaker and other people were given permission. The bare infinitive "use" is used after the verb "let" to show what action they were given permission to do. The possessive pronoun "her" shows that the flat belongs to the speaker's sister. The word "for" indicates the purpose of using the flat.

4. I look forward to hearing from you soon.
Explanation: In this sentence, "look forward to" is a phrasal verb indicating anticipation or excitement for something in the future. The -ing form of the verb "hear" is used after the preposition "to" to show what action the speaker is anticipating. The pronoun "you" refers to the person the speaker is expecting a response from. The word "soon" indicates the expected time when the speaker wants to hear from the person.

5. We stopped reading when the bell rang.
Explanation: In this sentence, "stopped" is the main verb indicating an action of ceasing or interrupting an ongoing action. The -ing form of the verb "read" is used after the verb "stopped" to show what action they ceased. The word "when" indicates the trigger or moment that caused them to stop reading. The verb "rang" indicates that the bell made a sound.

6. She forgot to pay the phone bill.
Explanation: In this sentence, "forgot" is the main verb indicating an action of not remembering or neglecting to do something. The infinitive "to pay" is used after the verb "forgot" to show what action she neglected to do. The noun phrase "the phone bill" indicates the specific bill that she was supposed to pay.

7. I remember giving you the key before I left.
Explanation: In this sentence, "remember" is the main verb indicating an action of recalling or having a memory of something. The -ing form of the verb "give" is used after the verb "remember" to show what action the speaker had a memory of. The pronoun "you" refers to the person to whom the speaker gave the key. The word "before" indicates the time when the action of giving the key occurred. The pronoun "I" indicates that it was the speaker who gave the key.

8. My mother made me clean the window.
Explanation: In this sentence, "made" is the main verb indicating an action of forcing or compelling someone to do something. The object pronoun "me" shows that the speaker was the one who was forced to do the action. The bare infinitive "clean" is used after the verb "made" to show what action they were forced to do. The noun phrase "the window" indicates the specific thing they were forced to clean.

9. Anna forgot to take out the rubbish last night.
Explanation: In this sentence, "forgot" is the main verb indicating an action of not remembering or neglecting to do something. The infinitive "to take" is used after the verb "forgot" to show what action Anna neglected to do. The noun phrase "the rubbish" indicates the specific thing Anna was supposed to take out. The phrase "last night" indicates the time when Anna forgot to take out the rubbish.

10. Sara said she would order a pizza for dinner.
Explanation: In this sentence, "said" is the main verb indicating an action of expressing words or information. The pronoun "she" refers to Sara, the person who spoke. The modal verb "would" is used after the verb "said" to show Sara's intention or plan. The bare infinitive "order" is used after the modal verb "would" to show what action Sara intended to do. The noun phrase "a pizza" indicates the specific thing Sara intended to order. The phrase "for dinner" indicates the time or purpose for which Sara intended to order the pizza.