Learn Dutch: Niet alleen de ballon, maar ook de taart moet strakjes onopgemerkt blijven. - Not only the balloon, but also the cake must remain unnoticed later.

Strakjes is an adverbial diminutive of time, formed by adding -jes to straks (later/in a bit). While both mean the same thing, strakjes sounds softer, more casual, and often implies that the wait will be very short.

Why is the verb moet singular when both a balloon and a cake are mentioned?

In sentences using the niet alleen A, maar ook B (not only A, but also B) structure, the verb usually agrees with the part of the subject that is closest to it. Here, that is the singular de taart, so we use moet.

How is the word onopgemerkt put together?

It is built from the separable verb opmerken (to notice). First, it becomes the past participle opgemerkt (noticed). Then, the prefix on- is added to make it negative, creating onopgemerkt (unnoticed).

What grammatical rule puts onopgemerkt blijven at the end of this sentence?

The sentence uses the modal verb moeten (must). The conjugated form moet takes the second position right after the long subject phrase. In Dutch, modal verbs push the main verb (blijven) and closely related adjectives or participles (onopgemerkt) all the way to the end of the clause.