關(guān)于else

請(qǐng)問(wèn)，多個(gè)條件選擇時(shí)，是否需要加else，即

if.............then begin.....................end

if.............then begin.....................end

if.............then begin.....................end

還是要

if.............then begin.....................end

else if.............then begin.....................end

else if.............then begin.....................end

??

加與不加有什么區(qū)別嗎