display: -webkit-flex; 手机上图下文字，pad上有浮动。

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    <div class="boxt">
    <div class="boxt-right"><img src="data:images/c0401-002-s.png"/></div>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>

    </div>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>
    <section class="boxt-left">3．You may have noticed that all three of these words are similar to <i class="red">say</i> in that they have meanings that are connected with <i>showing, telling</i> or <i>explaining</i>. But do you know how to use them c</section>

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