This sentence is past tense because it's talking about something that happened yesterday. 

When a sentence is past tense, we add -ed to the verb. The verb from the answer choices is "walk", so the correct answer is "walked". 

Yesterday I walked to school. 

This sentence is about something that is going to happen in the future. We know this because of the word "tomorrow". 

When a sentence tells about the future, we add "will" before the verb. The verb from the answer choices is "walk", so the correct answer is "will walk". 

Tomorrow I will walk to school. 

This sentence is talking about something that is taking place right now. This is a present tense sentence.   

When a sentence is in present tense, the verb normally has no ending added to it. The verb from the answer choices is "walk", so the correct answer is "walk". 

Today I walk to school. 

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is past tense because it's talking about something that happened yesterday. 

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is past tense because it's talking about something that happened yesterday. 

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is about something that is going to happen in the future. We know this because of the word "tomorrow". 

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is about something that is going to happen in the future. We know this because of the word "tomorrow". 

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is talking about something that is taking place right now. This is a present tense sentence.

When a sentence is past tense, we add -ed to the verb

When a sentence tells about the future, we add "will" before the verb. 

When a sentence is in present tense, the verb normally has no ending added to it.

This sentence is talking about something that is taking place right now. This is a present tense sentence.

This sentence is past tense because it starts by saying "yesterday". Given the choices, we are looking for the past tense form of "walk". When we make a verb past tense, we add "ed" to the end of the word. This means that "walked" is the correct answer.