Conditionals (Zero, first, second, third); Unless, in case, provided that, I wish/It only: Mixed conditionals 1 Complete the text with the correct form of the verbs given. Science or accident? For years scientists have conducted experiments. In many cases, this has led to great scientific discoveries However, don't forget that some important scientific breakthroughs occurred accidentally For example, if Charles Darwin (1) (not travel) to the Galapagos Islands, he wouldn't have noticed the differences between the same species of animal on the different islands. If he hadn't noticed these differences, he (2) (not come up with) his theory of evolution If Alexander Fleming (3) (be) a tidier scientist, he wouldn't have left some germ cultures in his lab while he went on holiday. If he hadn't been so observant, he (4) (not notice that one culture had been contaminated on his return. If he hadn't checked the contaminated culture, he (5) (not discover) penicillin. Finally, if Percy Spencer (6) [ignore) the melted chocolate bar in his pocket while he was working near an active radar set, he wouldn't have investigated it. If he (7) (not investigate) it, he (8) (not invent) the microwave