大错特错: completely mistaken; absolutely wrong; all wet; be all wrong; be far from being in the right; be grievously [gravely] mistaken; can hardly be more mistaken; commit a very grave [gross] err
认为: think; consider; hold; deem; take for; regard as; look upon as; take sb. [sth.] as; be known as; set down as 短语和例子认为无用的规定 stipulation deemed not to be written; 认为十拿九稳 take ... for granted;