80. A report by the American Academy for the Advancement of Science has concluded that much of the currently uncontrolled dioxins to which North Americans are exposed comes from the incineration of wastes. (A) much of the currently uncontrolled dioxins to which North Americans are exposed comes (B) much of the currently uncontrolled dioxins that North Americans are exposed to come (C) much of the dioxins that are currently uncontrolled and that North Americans are exposed to comes (D) many of the dioxins that are currently uncontrolled and North Americans are exposed to come (E) many of the currently uncontrolled dioxins to 答案为E D中少了that,想问下that在从句中做主语时可否有that is..and is....在这种情况下是否也许不出才能平行?