中4生物考試主要考咩??

do you mean mid-term exam?

MUST exam:
1. Classification of living things (memorize the characteristics of different kinds of living things)
2. Cells (functions and characteristics of different parts of a cell)

MAY exam (depend on which school you are studying, better ask your schoolmates):
1. Food and Nutrition (digestion; memoerize names of enzymes and functions of different organs)
2. Nutrition of plants (transpiration and mainly distinguish photosynthesis (with light) and respiration(no light))
3. Respiration (mainly distinguish aerobic and anaerobic respiration)
4. Gas Exchange (inhalation and exhalation)

LITTLE TIPS: memorize all specific names (organs, parts of cells or organs, enzymes); i suggest you to write some tables and group the names together. for me, i usually make my own notes and diagrams for exam, this really help you to memorize something after you write it out for once (much better than just read and look). but of course, different methods depend on how much time do you have. ADD OIL ~~

光合作用(光反應,暗反應)要識睇圖呀
呼吸作用(需氧,缺氧運動)要識睇圖
細胞(植物,動物)等等