让我们来谈谈七个常见的频率副词：always、often、usually、sometimes、occasionally、rarely 和 never。这些小词在日常对话中起着重要作用，一旦你掌握了它们的用法，说话就会显得自然得多。

什么时候用“have to”，什么时候用“must”？前者用于表示外部义务，后者用于表示内部义务。让我们来谈谈这两者的区别，以及如何正确地构成疑问句和变位时态。

你可能已经知道，“have”用于表达所有权。然而，当加上介词“to”时，其含义便从所有权转变为义务。让我们进一步探讨“have to”的用法及其适用场景。

In this post, we’ll explore gerunds, how they’re different from other -ing verbs (like the present, future, and past continuous), and how you can start using them naturally in your speaking and writing. There are also practice exercises to test your knowledge and tips on how to continue learning gerunds on your own.

When is it okay to drop pronouns and auxiliary verbs in English? Some languages do it often, but what about English? Let's find out!