fix bug

apps/classroom/Tpl/default/Index/theme_x7_w3g.html

@@ -92,7 +92,7 @@
 									<div class="home_item_mark_orange layout_center">付费</div>
 								</if>
 								<span class="text_14_600 color_333333 weight_full van-multi-ellipsis--l2" style="margin-right: 1.5rem;margin-left: 0.625rem;">{$vo['exams_paper_title']}</span>
-								<if condition="$vo['price'] eq 0">
+								<if condition="$vo['price'] eq 0 or $vo['is_buy'] eq 1">
 									<div @click="onStart({$vo['exams_paper_id']})" class="home_button_green layout_center">开始做题</div>
 									<else />
 									<div @click="onPay({$vo['exams_paper_id']})" class="home_button_orange layout_center">¥{$vo['price']}</div>