MODAL HAVE TO	Pp+Have to/ has to+ Sf verb	pp+  do not //doesn’t have to+   sf verb		Do //does+ pp + have to+ sf verb		MODAL HAD TO	Pp +had to + sf verb	Pp + did not +have to+ sf verb	did+  pp +  have to+ sf verb
PP	POSITIVE        +	NEGATIVE        -		INTERROGATIVE   ?		PP	POSITIVE     +	NEGATIVE      -	INTERROGATIVE   ?
EXAMPLE	I have to be home by eight	I don´t have to be home by eight		Do I have to be home by eight?		EXAMPLE	I had to be home by eight	I didn´t have to be home by eight	did I have to be home by eight?
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY

MODAL         MUST	Pp+ must + Sf verb	pp+  must not +   sf verb		Must + pp + sf verb		MODAL SHOULD	Pp +should + sf verb	Pp +should +  not + sf verb	should +  pp +  sf verb
PP	POSITIVE        +	NEGATIVE        -		INTERROGATIVE   ?		PP	POSITIVE     +	NEGATIVE      -	INTERROGATIVE   ?
EXAMPLE	I must take exam	I musn´t take exam		Must I take exam?		EXAMPLE	I should study harder	You shouldn´t copy	Should I go?
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY
I						I
YOU						YOU
HE						HE
SHE						SHE
IT						IT
WE						WE
YOU						YOU
THEY						THEY