So far, we have seen tenses only just before the selbri, or (equivalently in meaning) floating about the bridi with ku. There is another major use for tenses in Lojban: as sumtcita, or argument tags. A tense may be used to add spatial or temporal information to a bridi as, in effect, an additional place:

Here ca does not appear before the selbri, nor with ku; instead, it governs the following sumti, the le nu construct. What Example 10.69 asserts is that the action of the main bridi is happening at the same time as the event mentioned by that sumti. So ca, which means “now” when used with a selbri, means “simultaneously-with” when used with a sumti. Consider another example:

The second pu is simply the past tense marker for the event of your going to the house, and says that this event is in the speaker's past. How are we to understand the first pu, the sumtcita?

All of our imaginary journeys so far have started at the speaker's location in space and time. Now we are specifying an imaginary journey that starts at a different location, namely at the event of your going to the house. Example 10.70 then says that my going to the market is in the past, relative not to the speaker's present moment, but instead relative to the moment when you went to the house. Example 10.70 can therefore be translated:

(Other translations are possible, depending on the ever-present context.) Spatial direction and distance sumtcita are exactly analogous:

The event contours of selma'o ZAhO (and their space equivalents, prefixed with fe'e) are also useful as sumtcita. The interpretation of ZAhO tcita differs from that of FAhA, VA, PU, and ZI tcita, however. The event described in the sumti is viewed as a process, and the action of the main bridi occurs at the phase of the process which the ZAhO specifies, or at least some part of that phase. The action of the main bridi itself is seen as a point event, so that there is no issue about which phase of the main bridi is intended. For example:

Here the (point-)event of my being dead is the portion of my living-process which occurs after the process is complete. Contrast Example 10.74 with:

As explained in Section 10.6, Example 10.75 does not exclude the possibility that I died before I ceased to live!

Likewise, we might say:

which indicates that before my eating begins, I go to the store, whereas

would indicate that I go to the store after I am finished eating.

Here is an example which mixes temporal ZAhO (as a tense) and spatial ZAhO (as a sumtcita):

Probably it sailed up onto the dock. One point of clarification: although xelklama appears to mean simply “is-a-mode-of-transport”, it does not – the bridi of Example 10.78 has four omitted arguments, and thus has the (physical) journey which goes on too long as part of its meaning.

The remaining tense cmavo, which have to do with interval size, dimension, and continuousness (or lack thereof) are interpreted to let the sumti specify the particular interval over which the main bridi operates:

Be careful not to confuse a tense used as a sumtcita with a tense used within a seltcita sumti:

claims that the interval specified by “this winter” is long, as events of snowfall go, whereas

claims that during some part of the winter, which is long as winters go, snow falls.