probably

Compared meaning: very likely, probably true (adverb).

比较义项：很可能，大概（副词）。

• probably 本词

  The default, all-purpose way to state likelihood in everyday speech; used freely with any verb, needs no intensifier, and sits naturally between the subject and the verb or right after 'will'.

  probably 是日常口语中最常用、最百搭的说法，可以自由地用于任何动词，不需要搭配程度词，通常直接放在主语和动词之间，或紧跟在“will”之后。

  It will probably rain later, so bring an umbrella with you.

  待会儿很可能会下雨，所以带上雨伞吧。

• likely

  As a plain sentence adverb it sounds more formal or written (common in news style as 'will likely'); more often it appears as an adjective in the pattern 'be likely to do something'.

  likely 单独作句子副词时听起来更正式、更书面（常见于新闻文体的“will likely”结构）；它更常以形容词形式出现，用在“be likely to do something”这个句型里。

  It is likely to rain later this afternoon.

  今天下午很可能会下雨。

Probably and likely both mean very likely to be true. Probably is the everyday, default word for any verb. Likely as an adverb is more formal, as in will likely. Likely is usually an adjective, as in be likely to; that use is not compared.

probably 和 likely 在表示“很可能”时意思很接近，但语体和搭配不同：probably 是日常口语里最常用、最随意的说法，likely 单独作副词时略显正式，且常需要程度词或和 be 搭配。这里不比较 likely 作形容词（有可能的，如 a likely outcome）的用法。