shoulder of trough valley
fault trough submarine valley
upper trough (upper-level trough)
upper trough lower trough coupling
Wiring Trough， Wiring Groove， Cable Trough
glacial valley (galical-carved valley)
The super-wisdom valley The Bo Ruo Valley
The super-wisdom valley(The Bo Ruo Valley)
U-shaped valley(U-valley)
V-shaped valley(V-valley)
5-trough cleaning method
across settlement trough
adjustable feeding trough