-Shall I tell john about it?-No,you ______.Idon't know his telephone number.

-Shall I tell john about it?-No,you ______.Idon't know his telephone number.
-Shall I tell john about it?-No,you ______.Idon't know his telephone number.

-Shall I tell john about it?-No,you ______.Idon't know his telephone number.
can't
从尾句Idon't know his telephone number.得出是客观上无法告知john,而不是主观上不告知.所以应该用受限回答.