considerable

Compared meaning: large in amount, degree, or importance (adjective).

比较义项：数量、程度或重要性上「相当大，可观」（形容词）。

• substantial

  Stresses the importance or significance of the amount, not just its size; common with progress, evidence, majority, difference; more formal and often implies a meaningful, weighty change.

  强调数量或程度的重要性与分量，而不只是大小；常与progress（进展）、evidence（证据）、majority（多数）、difference（差异）等词搭配；语气更正式，常暗示有意义的、分量十足的变化。

  Winning that client made a substantial difference to the company's finances.

  赢得那位客户给公司的财务状况带来了显著的变化。

• considerable 本词

  Simply marks an amount or degree as large enough to be noticeable, without extra connotation of importance or approval; very common with money, time, effort, distance.

  只是单纯表示数量或程度大到足以引起注意，不带有额外的重要性或赞许含义；常与money（金钱）、time（时间）、effort（努力）、distance（距离）等词搭配，非常常见。

  It took considerable effort to convince him to change his mind.

  说服他改变主意花费了相当大的努力。

• respectable

  Implies the amount is large enough to be viewed favorably relative to expectations, often about salaries, scores or times; carries a mild tone of approval rather than pure emphasis on size.

  暗示这一数量相对于预期而言已经达到令人满意的水平，常用于薪水、分数或用时等场合；带有一丝赞许的语气，而不是单纯强调数量之大。

  He finished the marathon in a respectable four hours.

  他以令人满意的四小时跑完了马拉松。

Substantial, considerable and respectable can all describe a large amount, but the tone differs. Substantial stresses importance, not just size, often for progress. Considerable marks an amount as large enough to notice, common with money. Respectable implies the amount is large enough to seem favorable.

这三个词都可以表示数量或程度相当大，但语气和搭配不同：substantial强调重要性和分量，considerable只是客观地表示数量大，respectable则带有「达到令人满意的水平」的赞许意味。这里不比较respectable表示「体面的，受人尊敬的（人或行为）」的常见义项，也不比较substantial表示「坚固的，实质性的」的义项。