translation - How to say, "try to __", "have to __"

For some reason I can't remember how to say "try to _" or "have to (must) _" in Japanese. How can I say this? Any variations you can include would be appreciated.

Answer

Try to ~

~ようとする (Does not give any information whether the action was actually carried out in entirety)

~てみる (Try for the sake of seeing the result, does not have negative implication as in "to try (unsuccessfully )" )

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have to(must) ~

~なければならない

~なくては｛ならない・いけない｝

~ないといけない

~ねばならない

~なくては　is often contracted to ~なくちゃ

~なければならない can also be contracted and have ならない elided to form "~なけりゃ" or "~なきゃ" which is used informally.