Jawaban:

The living room was so untidy (that) they could not find anything they were looking for. (Ruang tamunya sangat berantakan sehingga mereka tidak dapat menemukan apa yang mereka cari.)

The audio sounds so loudly (that) I have a headache. (Suara audionya sangat kencang hingga aku merasa pusing.)

She drove so quickly (that) she almost hit a tree. (Dia mengendarai dengan sangat cepat sehingga hampir menabrak pohon.)

The child sings so beautifully (that) the audience are amazed by his voice. (Anak itu bernyanyi dengan sangat indah sehingga seluruh penonton mengagumi suaranya.)