### Instruction:

Extract the cause and effect entities from the following sentence:
When several attributes form the primary id, each attribute is separated by a plus sign ("+"), and should appear on a line of its own; the last attribute may be followed by a period (".")

### Assistant:

KEYWORD: When
VARIABLE: the last attribute
CONDITION: may be followed by a period
CAUSE_1: several attributes form the primary id
NOT_RELEVANT: (".")
AND: and
EFFECT_1: each attribute is separated by a plus sign
EFFECT_2: should appear on a line of its own
EFFECT_3: the last attribute may be followed by a period

