There is a relationship model reflecting teachers' participation in scientific research projects ：
R（ Teacher number , Project name , Scientific research workload , Project category , Project amount , person in charge ）
If it is stipulated that ： More than one person can participate in each project , Each teacher has a scientific research workload for each project ; Each item belongs to only one category , Only one person in charge .
（1） According to the above , Write mode R Basic functional dependencies and main codes .
（2） explain R No 2NF The reason of .
（3） take R Specification to 3NF.