因果关系词：because; for; since; as; therefore; consequently; hence; so; thus; so…that; such… that; in order that; accordingly(因此;于是;相应地); due to; thanks to; as a result; in that(= because); now that(既然); because of; considering that, seeing that; in response to; for this reason;

转折关系词：but; however; on the contrary; contrarily; by contrast; in contrast; conversely; instead of ; rather than; unlike, on the other hand; unfortunately;