anyone would think (something)
It seems that something is true, even though it isn't. This phrase is usually used when someone is acting in a unusual manner. Why are you so nervous? Geez, anyone would think you'd never given a presentation before.
anyone would ˈthink (that)...
(also you would have ˈthought (that)...) (of somebody’s strange or surprising behaviour) if you did not know the truth, it would seem that...: Don’t be so nervous! Anyone would think you’d never been to a party before!