Time expressions in Japanese are really important. They help you know which verb forms to use in sentences. This change isn’t just about the tense of the verb; it can also change the meaning or feeling of what you are saying.

In Japanese, verbs generally fall into three main tenses: present (or future), past, and negative. The time expression you choose can change how these tenses are understood. For example:

• To say "I eat sushi," you would say 寿司を食べます (sushi o tabemasu) in the present tense.
• To say "I ate sushi," you'd say 寿司を食べました (sushi o tabemashita) in the past tense.

Japanese has time expressions like 今 (ima) which means "now," 昨日 (kinō) meaning "yesterday," and 明日 (ashita) meaning "tomorrow." These words tell you which tense to use.

For example, if you want to discuss a future plan, using 明日 (ashita) lets you know to use the present or future form of the verb. So, "I will eat sushi tomorrow" translates to 明日寿司を食べます (ashita sushi o tabemasu).

You also have to pay attention to how these time expressions change the meaning. For instance, 今 (ima) suggests something happening right now, but 急がなければならない (isoganakereba naranai) means something must happen really soon.

So, if you want to say "I must eat sushi now," you can say 今すぐ寿司を食べなければならない (ima sugu sushi o tabenakereba naranai). This shows that it needs to be done immediately.

When it comes to negative forms, you also need to be aware of time expressions. If you want to say "I didn’t eat sushi yesterday," you would say 昨日寿司を食べませんでした (kinō sushi o tabemasen deshita). Here, 昨日 (kinō) clearly indicates that the action happened in the past, and the negative form changes the meaning a lot.

Context is really important in Japanese too. It can change how polite you need to be. For example, the way you say "I will eat sushi" can differ depending on the situation. In a polite context, you might say 私は寿司をいただきます (watashi wa sushi o itadakimasu), while in a casual chat, you could just say 寿司を食べる (sushi o taberu).

Other time expressions like 毎日 (mainichi - "every day") or たまに (tamani - "sometimes") can also affect the verb form. For example:

• "I eat sushi every day" translates to 毎日寿司を食べます (mainichi sushi o tabemasu).
• "I sometimes eat sushi" becomes たまに寿司を食べます (tamani sushi o tabemasu).

Both of these keep the present tense because they describe actions that happen regularly.

In short, understanding how Japanese time expressions affect verb forms helps you create clear and accurate sentences. By noticing the small differences these expressions make to tense, politeness, and meaning, you'll improve your grammar skills and communicate better in Japanese. With regular practice using different time expressions, verb forms, and their contexts, you'll get really good at this part of the language.