English tenses are used with adverbs and adverbial phrases that indicate the time of the action, for example, yesterday, now, often, tomorrow, an hour ago, last week. Adverbs of time and adverbial phrases of time are often called “time expressions”.
Certain adverbs of time and adverbial phrases of time require certain tenses. For example, if you say yesterday or last week, you will use the past tense, not the present, right? The connection between the tense and its adverbs and adverbial phrases of time is something that can’t be ignored. In fact, understanding this connection is the key to correct use of English tenses.
• I have just seen him.
• I saw him a minute ago.
Maybe “I have just seen him” happened earlier than “I saw him a minute ago”. We use the present perfect in the first sentence, and use the simple past in the second sentence because just and a minute ago show the necessity to use these tenses.
So, there is a clear connection between the tense and its adverbs of time and adverbial phrases of time. This connection will help us to understand how English tenses are used.
• usually: simple present
• now: present continuous
• already: present perfect
• for three hours, already: present perfect continuous
• yesterday: simple past
Not all adverbs and adverbial phrases of time call for certain tenses. For example, the adverb soon. You can say: He left soon. He will leave soon. The adverb soon doesn’t call for a specific tense and doesn’t help us to choose the tense correctly.
Native speakers sometimes omit expressions indicating time (if the context is clear) because the tense form itself conveys general information about the time of the action. For example, the sentences in the following pairs have practically the same meaning:
I buy bread in this store. (usually)
I usually buy bread in this store.
She’s watching TV. (now)
She’s watching TV now.
He has left. (already)
He has already left.
However, language learners can’t allow themselves such familiarity with tenses. You need to establish a clear connection between the tense and its adverbs of time. Always analyze why this or that adverb of time is used in the sentence and in what meaning, and what adverb of time you should put in if it is not there. This will help you to understand what English tenses mean and how they work, and you will quickly learn how to use them correctly and confidently.
Good knowledge of various expressions denoting time is necessary for understanding and using English tenses.