Two time-position adverbials may enter into a hierarchical relation and occur in one sentence. The superordinate adverbial (the one denoting the more extended period) comes first, followed by the subordinate unit (the one denoting the less extended period). Their sequence is controlled by the general Principle of Whole-Before-Part, so a bigger unit of time or place always precedes a smaller unit of time or place. For instance:
Māma shì zuótiān xiàwǔ sān diǎnzhōng dào de
(Mother arrived at three o’clock yesterday afternoon.)
In this case, the two adverbials ‘xiàwǔ’ (afternoon) and ‘sān diǎnzhōng’(three o’clock) are both predicate adverbials (i.e., the time adverbial qualifies the predicate) hierarchically related. The superordinate unit can function as a sentence adverbial, and appear in the initial position of the sentence:
Zuótiān xiàwǔ māma shì sān diǎnzhōng dào de .
(Yesterday afternoon Mother arrived at three o’clock.)
*Sān diǎnzhōng māma shì zuótiān xiàwǔ dào de .
(*At three o’clock yesterday afternoon Mother arrived.)
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.