t<form>
  <div class="form-row">
    <div class="form-group col-md-6">
      <label for="firstname" class="col-form-label">firstname</label>
      <input type="text" class="form-control is-valid" id="firstname" placeholder="First name" value="Mark" required>
    </div>
    <div class="form-froup col-md-6">
      <label for="lastname" class="col-form-label">lastname</label>
      <input type="text" class="form-control is-valid" id="lastname" placeholder="Last name" value="Otto" required>
    </div>
  </div>
  <div class="form-row">
    <div class="form-group col-md-6">
       <label for="validationServer01">City</label>
       <input id="validationServer01" type="text" placeholder="City" class="form-control is-invalid" required>
      <div class="invalid-feedback">
        Please provide a valid city.
      </div>
    </div>
    <div class="form-group col-md-3">
      <label for="validationServer02">State</label>
      <input id="validationServer02" type="text" placeholder="State"  class="form-control is-invalid" required>
      <div class="invalid-feedback">
        Please provid a valid State
      </div>
    </div>
    <div class="form-group col-md-3">
      <label for="validationServer03">Road</label>
      <input id="validationServer03" type="text" placeholder="Road"  class="form-control is-invalid" required>
      <div class="invalid-feedback">
        Please provid a valid Road
      </div>
    </div>
  </div>
  <button type="submit" class="btn btn-primary">提交表單</button>
</form>