problematic：有疑问的，未解决的，未定的 

词根词缀：pro-前 +blem扔,抛 + -atic形容词词尾

• cathedral
• cathedral
• Catherine wheel
• catheter
• cathode
• Catholic
• catholic
• cation
• catkin
• catmint
• catnap
• catsuit
• cattery
• cattle
• catty
• catty-cornered
• catwalk T
• caucus
• cauldron
• cauliflower
• caulk
• causal
• cause
• cause celebre
• causeway