と([思「おも」]う、[言「い」]う、[考「かんが」]える) => That A N4
Particles
わけがない => There's no reason for A (A should not be possible) N3
Potential, Possibility
なくてはいけない => Must do A; have to A N4
Can, Should, Must
てはいけない => May not A, must not A N4
Can, Should, Must
に[違「ちが」]いない => Without a doubt, A N2
Information, Report
てしょうがない/てしかたがない => Very A; Really A; Extremely A N2
Degree, Level, Amount
[決「けっ」]して~ない => Won’t, isn’t N3
Will, Decision, Doing
わけにはいかない => Must not A, Must A N3
Needs, Requirement
なければならない => Must do A; have to A N4
Can, Should, Must
ない[方「ほう」]がよい => It would be better to not A N4
Can, Should, Must
はずがない => Cannot be A, should not be A N4
Sentence Endings
ようがない => There is no way to do A N2
Potential, Possibility