Sentence pattern for asking "should I do A or B?"

Question

We commonly encounter situations when there are a number of options and we would like to ask for instructions as to which option to choose. Here is a real example from my recent experience. I was trying to fill in a form but was not sure what to write in a box. I then asked

この欄に、携帯番号を記入しますか？それとも、空白にしますか？

In English, the direct translation would be

In this box, will I write my mobile number? Or, will I leave it blank?

But what I really wanted ask was

In this box, should I write my mobile number? Or, should I leave it blank?

In situations like the above, what sentence pattern in Japanese should I use?

Perhaps sentence patterns are not exactly the right thing to ask for. I think I might be digging into modality here, and would be grateful if someone could elaborate on this.

Answer 1

verb(plain form) + ”べき”

In your example, ”この欄に携帯番号を記入するべきですか？それとも、空白にするべきですか？”.

Example 記入する + べき = 記入するべき(I should write) 食べる + べき = 食べるべき(I should eat)