消失 + 在 + 茫茫大海 + 中
茫茫大海 (mángmáng dàhǎi) is a noun phrase meaning 'vast ocean' or 'boundless sea.' It combines 茫茫 (vast, boundless) with 大海 (ocean). It is a literary expression used to emphasize the immense, endless expanse of the sea.
小船漂入茫茫大海,再也看不到岸边。
Xiǎo chuán piāo rù mángmáng dàhǎi, zài yě kàn bù dào ànbiān.
The small boat drifted into the vast ocean, and the shore could no longer be seen.
一个人面对茫茫大海,心里既害怕又感到渺小。
Yī gè rén miànduì mángmáng dàhǎi, xīnlǐ jì hàipà yòu gǎndào miǎoxiǎo.
Facing the vast ocean alone, one feels both afraid and insignificant.
渔夫望着茫茫大海,等待着鱼群的到来。
Yúfū wàng zhe mángmáng dàhǎi, děngdài zhe yúqún de dàolái.
The fisherman gazed at the vast ocean, waiting for the schools of fish to arrive.