We can say: The expression, “B can continue the
series”, is used under different circumstances to make different
distinctions.
Thus it may distinguish
a) between the case when a man
knows the formula and the case when he doesn't; or
b) between the case when a man knows the formula and
hasn't forgotten how to write the numerals of the decimal
system, and the case when he knows the formula and has forgotten how to
write the numerals; or
c) (as perhaps in 64))
between the case when a man is feel
ing
60.
his normal self and the case
when he is still in a condition of shell shock; or
d)
between the case of a man who has done this kind of exercise before and
the case of a man who is new at it.
These are only a few of a large family of cases.