A semiconductor is a material with a _____.A.conductivity higher than a normal conductorB.

He is collecting materials for a book.（英译中)

Jim is going to get material for a new book.（英译中)

听力原文：（A) Some building materials are piled up on the ground.（B) A brick wall is being

Beef is an excellent material of iron.A.beginningB.storageC.sourceD.substance

Which of the following is the best material for an auditory learner？A．A recording.B．A vide

There is a tale that straw is the worst material from which to build a house, particularly