1. confusing / puzzling
confusing：指两个或以上的事物因有相似之处而“令人混淆、模糊不清、难以理解”，(difficult to understand, not clear)
e.g. The constructions on the box are very confusing.
This is a confusing word because it has two opposite meanings.
puzzling：指对某些事物的出处、来龙去脉、或如何解决感到棘手、为难。
e.g. For me, some English words are confusing, but not puzzling.
The situation was more puzzling than ever before.
2. be made up of / be made of / be made from / be made out of
be made up of：由……组合/装而成
e.g. Our class is made up of 45 students, 22 boys and 23 girls.
