Karst trough valley

shoulder of trough valley

fault trough submarine valley

upper trough lower trough coupling

The super-wisdom valley The Bo Ruo Valley

valley in valley

Valley-in-Valley

acclivitous trough

across settlement trough

adjustable feeding trough

agitated trough dryer

air trough board

Alumina-magnesia tilting trough

aluminium electrolysis trough

America trough

anchored trough

arc trough

around Kaijiang-Liangping Trough

auto-water trough