Spot Dictation (P222) It is said that scientists in the developed countries are trying to breed a tree that will be ideal |(理想的)| for city life. They say that in many cities the air is so ________(S1) that the plain, old-fashioned tree is bound to ________(S2). The ideal city tree must have ________(S3) roots. Roots that go down too far get in the way of underground ________(S4). It must have fairly short branches. Branches that ________(S5) too high stand in the way of overhead lines. The new type of tree must not drop heavy ________(S6) on people's heads, either. But _________________(S7), the ideal tree for the city must be tough. Carbon monoxide and other deadly gases in the ____________(S8) make it hard for the plain, old-fashioned tree to ________(S9). The ideal city tree, therefore, must be so tough that it will be able to ________(S10) the effects of the pollution in the air.