Read each pattern and its example, then write your own sentence on the line.
〜間際に N + 間際に／V-dict + 間際に
'Just before' a moment that is about to arrive, often with a sense of rush or bad timing. Attaches to nouns or dictionary-form verbs; neutral register, common at work.
発車間際に飛び乗って、何とか間に合った。 I jumped on just before the train left and barely made it.
〜まじき N + にあるまじき + N／V-dict + まじき + N
Classical negative 'must not / ought never to', used to condemn behavior unworthy of a role. Almost always in the set phrase N + にあるまじき + noun. Very formal written style.
教師にあるまじき発言だと批判が集まった。 Criticism poured in that the remark was unbecoming of a teacher.
〜までだ / 〜までのことだ V-dict + までだ（対処）／V-ta + までだ（弁明）
With V-dict it means 'I'll simply do X, that's all' — a calm fallback plan. With V-ta it means 'I merely did X, nothing more'. Formal, slightly stiff spoken and written.
断られたら、また別の会社を当たるまでだ。 If they turn us down, we'll simply approach another company.
〜まみれ N（泥・汗・借金 等）+ まみれ(の N)
'Covered all over in' an unpleasant substance such as mud, blood, dust or sweat; also figuratively 借金まみれ. Always negative. Neutral register, common in speech and writing.
工場から出てきた彼は、油まみれだった。 He came out of the factory covered in oil.
〜めく N（春・皮肉・謎 等）+ めく → めいた／めいて
Turns a noun into a verb meaning 'take on the air of / show signs of X'. Mostly seen as 〜めいた or 〜めいて; a literary, slightly poetic word used for seasons and tones of speech.
三月に入り、日ごとに春めいてきた。 Now that March has come, it grows more spring-like by the day.
〜もさることながら N + もさることながら（後件を強調）
'A is certainly true, but B is even more so' — you admit the first point and then put greater weight on the second. Formal written style, common in reviews and speeches.
味もさることながら、この店は接客が素晴らしい。 The food is good, of course, but the service at this place is superb.