have to

should not

can't

must not

    I’m    sure    about    this.

    I’m    not    sure    about    this.

must

can

would

ought to

I    think    you    should    take    a    taxi.

Taxis    are    better    than    buses.

I’m    sure    this    happened.

I’m    not    sure    this    happened.

I    think    they    sent    an    email.

I    don’t    think    they    sent    an    email.

I    think    taxes    aren’t    high    enough.    

B        I    think    taxes    are    too    high.

    My    boss    told    me    to    do    this.

I    think    this    is    important    for    my    future.

have to

must

can

should

I    went    to    the    party.

I    didn’t    go    to    the    party.