$8.$ The lecture was interesting. It is also informative.

$→$ The lecture is both intersting and informative.

$→$ The lecture is not only interesting but also informative.

$9.$ She plays tennis and she plays badminton, too.

$→$ She plays not only tennis but also plays badminton.

$10.$ He is a singer and he is also an actor.

$→$ He is both a singer and an actor.

$-$ Form:

$+$ $S$ $+$ $V$ $+$ $not$ $only$ $+$ $adj$ $+$ $but$ $also$ $+$ $adj$.

$+$ $S$ $+$ $V$ $+$ $not$ $only$ $+$ $noun$ $+$ $but$ $also$ $+$ $noun$.

$+$ $S$ $+$ $V$ $+$ $not$ $only$ $+$ $V$ $+$ $but$ $also$ $+$ $V$.

$+$ $S$ $+$ $V$ $+$ $both$ $+$ $adj/noun$ $+$ $and$ $adj/noun$.

`8.`  

`->` The lecture is both intersting and informative

`=>` S + tobe + both + ... + and + ...

`->` The lecture is not only interesting but also informative

`=>` S + tobe + not only ..... but also ... : không chỉ ... mà còn

`9.` She plays not only tennis but also plays badminton

`=>` S + tobe + not only ..... but also ... : không chỉ ... mà còn

`10.` He is both a singer and an actor

`=>` S + tobe + both + ... + and + ...