沙壩

沙 = 少 + 氵 : Sherlock Holmes (sh) is selling bottles (氵) in front of the ashram (a1). Smiley (少) comes round because thon is very thirsty and buys a bottle, just to find out that it contains only sand (沙).

坝 = 土 + 贝 : The crab (贝) wants to use the ashram's bathroom (a4), but Beelzebub (b) built a dike (坝) made out of dirt (土) and the crab is unable to overcome the dike.