To complete the given sentences, you need to add the right words to make them full sentences. Here are some suggestions:
Shamik has finished his homework.
Grandfather is drinking a glass of water.
She has ten candies.
The cat is sleeping.
My school has a gym, which is good for health.
The book is on the table.
Open the door.
Switch off the lights after breakfast today.
He is riding a new car.
It is raining outside.
These sentences now have subjects and predicates, which form complete ideas. You can see how each sentence structure varies but follows a general pattern of including a subject (who or what the sentence is about) and a predicate (what the subject is doing). This helps ensure the sentences are clear and complete.