ne-height:0.8em;">
	间隔重复
	</div>
</span>
<span id="flashcard_intro_a_front">
	<div id="fc_words" class="fcard_center" style="height:2.5em">
	间隔重复 = <span class="underline">____</span> + <span class="underline">____</span>
	</div>
</span>
<span id="flashcard_intro_a_back">
	<div class="fcard_bg" src="pics/fcards_intro.png" sx=0 sy=240></div>
	<div id="fc_words" class="fcard_center" style="height:2.5em">
	测试 + 时间
	</div>
</span>
<span id="flashcard_intro_b_front">
	<div id="fc_words" c