1(i) -- Simple present: I write a letter to him
Simple past: I wrote a letter to him 

2(i) Simple present: I go to the school 
Simple past: I went to the school

3(i) -Simple present: She sings at Hard Rock Café
Simple past: She sang ar Hard Rock Café

4(r)- Simple present: He plays guitar
Simple past: He played guitar

5(i) -Simple present: Catarine buys gifts to her family
Simple past: Catarine bought gifts to her family

6(i) -Simple present: John understand the lesson
Simple past: John understood the lesson

7 (r) Simple present: The teacher opens the window
Simple past: The teacher opened the window

8-Simple present: My mom has a blue t-shirt
Simple past: My mom had a blue t-shirt

9(i) -Simple present: I see a bird on the tree
Simple past: I saw a bird on the tree

10(r) - Simple present: My friend arrive today
Simple past: My friend arrived yesterday
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