软底土的英文

• poor subsoil
• soft sub-soil

• 软:    soft; flexible; supple; plia ...
• 软底:    soft bottom
• 底土:    bottom soil; natural soil; pan; root clay; seat clay; seat earth; su oil; substratum; underclay; underearth; underground; underlying ground; undersoil
• 软底板:    soft floor; soft seat; softseat
• 软底片:    soft negative