that's really very easy ,
that's really very simple , even a ,,simple-mind'' could crack知道 it
that's really very simple , even a common simple kid in the street could get知道 it ,
just needless2explain any more ,
y[[=why]] do even those doctors博士 or professor e.t.c. still not b able 2 comprehend知道 it ??
y[[=why]] do even those doctors醫生 or professor e.t.c. still keep on restraining局限 themselves + others