1) You should practice speaking English regularly. It is necessary.
=>it….
2) Mary invited her friends to have a party last week.
=>she……
3)you are norlt allowed to use your mobile phone in the examination room (MUSTN’T)
=>the students…..
4) you gave her a bunch of rose last week.
=> it was….
\text{S + aux + V-bare}
$\text{It + tobe + S + who/that + V}$
$\boxed{\color{purple}{\text{#KaitoKid!}}}$