Just, Now, About To: vừa, đang, sắp

Vietnamese verbs never change form. To show how an action relates to now, put a marker directly before the verb:

• vừa, mới or vừa mới = just, a short time ago: Tôi vừa ăn xong. (I have just eaten.)
• đang = in progress now or at a given moment: Em ấy đang học bài. (She is studying.)
• sắp = about to, very soon, often with rồi at the end: Trời sắp mưa rồi. (It's about to rain.)

Let the context decide: bây giờ, hiện nay or a moment like lúc anh gọi (when you called) point to đang; a recent past such as tuần trước or được năm phút points to vừa; signs that something is coming point to sắp. đã and sẽ also mark past and future, but they don't say how close the event is.