... that _(1) _ can be an alternative source of energy B: Why you think so? A: Because our major sources of energy are running out while (2) B: However, _(3) _ (1): nuclear ... _(4) _ (1): water power (2): water is unlimited (3): It also provides energy without pollution (4): It is expensive to build a dam for hydroelectricity A: I think that _(1) _ can ... the environment (3) However, it is not available when there is no wind (4) A: I think that _(1) _ can be an alternative source of energy B: Why you think so? A: Because our major sources...