Hi.<br/>1. It happened the first time in 1900.<br/>2. It happened <b>for</b> the first time in 1900.<br/><br/>1. It happened a second time in 1915.<br/>2. It happened <b>for</b> a second time in 1915.<br/><br/>It seems English speakers use "for" or drop it arbitrarily. Is that correct?