So I have this XML:

```
<?xml version="1.0" encoding="utf-8"?>
<M_ChucVu>
  <ChucVu>
    <MaChucVu>1
    </MaChucVu>
    <TenChucVu>
    </TenChucVu>
  </ChucVu>
  <ChucVu>
    <MaChucVu>2
    </MaChucVu>
    <TenChucVu>
    </TenChucVu>
  </ChucVu>
  <ChucVu>
    <MaChucVu>23</MaChucVu>
    <TenChucVu>12</TenChucVu>
  </ChucVu>
  <ChucVu>
    <MaChucVu>44</MaChucVu>
    <TenChucVu>44</TenChucVu>
  </ChucVu>
</M_ChucVu>

```

and I want to retrieve the `ChucVu` tags that contain an empty `TenChucVu` tag so the result is this:

```
<ChucVu>
  <MaChucVu>1
  </MaChucVu>
  <TenChucVu>
  </TenChucVu>
</ChucVu>
<ChucVu>
  <MaChucVu>2
  </MaChucVu>
  <TenChucVu>
  </TenChucVu>
</ChucVu>

```