First, read the English article below.

Tap the Gmail app, which resembles a red "M" on a white background. This will open your Gmail inbox if you're logged in.  If you aren't logged in, you'll need to enter your email address and password when prompted. Unfortunately, you cannot recall an email sent from Gmail on Android. It's the pencil icon in the bottom-right corner of the screen. A new email form will appear. In the "To" text box, type in the email address of the person to whom you want to send an email. Type your email's subject into the "Subject" text box, then type whatever you want in the email's body. It's in the upper-right corner of the screen. Doing so will send your email. This option will appear in the lower-right corner of the screen. You'll have five seconds to recall the email. Once your email is recalled, it will reopen as a draft. You can edit or discard it from there. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Mở Gmail. Nhấn vào Compose. Nhập địa chỉ email người nhận. Thêm chủ đề và nội dung thư. Nhấn vào biểu tượng "Send" ở góc trên bên phải màn hình. Nhấn vào UNDO khi hiện ra. Xem lại email chưa gửi.