~ひょうしに(~拍子に)   => the moment [A], unintentionally / inadvertently caused something to happen N1
~ばよかった/~たらよかった/~ばよかったのに/~たらよかったのに => If only N3
ただし/ただ => right; correct. N2
… たら => Introduction N4
How to say the beginning
たとたん(に) => as soon as; just as ~ N3
…たりしたら/しては => ... Such as N3
Demonstrate by example
たり~たり => do such things as A and B N5
たぶん => Maybe... N4
Speculation
へた => Bad at... N5
Evaluate
または => or N4
…と…た => when... did N4
Continuous
また => (Choose) or N3
Selection