The correct participial form to fill in the blank is "attached."
The completed sentence would read: "The prototype of this collector has a conveyor belt attached to two pontoons, or rafts."
The prototype of this
collector has a conveyor belt attached to two pontoons, or rafts.
The correct participial form to fill in the blank is "attached."
The completed sentence would read: "The prototype of this collector has a conveyor belt attached to two pontoons, or rafts."