css如下:
.msg{
width:200px;height:50px;
margin-bottom: 20px;
background: #20B2AA;color:#fff;
text-align: center;line-height:50px;
position: relative;
border-radius:10px 10px 6px 10px;
}
.msg::after{
content: '';
display: block;
width:0;height:0;
border:solid 16px;
border-top:20px;
border-color:transparent transparent transparent #20B2AA;
position: absolute;
top:8px;right:-30px;
}
<div class="msg">你在干嘛呢?</div>
<div class="msg">我在吃饭,你了?</div>
<div class="msg">打算出去玩</div>