account for
有“說明、解釋…原因,對...負有責任,占有,占...百分比”等含義.
做“占...百分比”解釋,表示占有一定比例含義,多接分數,如一半、1/5等,當然也有接百分數的情況.
APEC members account for more than half of the world's economic output.
亞太經合組織成員的經濟總量在世界占一半以上.
Petrochemicals today account for one fourth of all the chemicals made, in ten years this amount is expected to double.
石油化工產品現在已占所有化學制品的四分之一,十年后預計這個數目還要加倍.
make up 含義較多,有“彌補、組成、化妝、整理”等含義.
但本意是“組成、構成”,有一個物體由幾部分拼湊、連接而成的含義,相當于 compose.
Farming and mining make up most of the country’s industry
The medical team was made up of twelve doctors.
The boy students in our class make up two fifths of the whole students.
take up沒有占多少百分比的意思　
主要含義：開始從事、占去時間（花費時間）、占去空間、拿起等
　When did he take up football?
　The work took up all his time.
　The piano takes up too much space.
He took up arms and rushed out.