In writing, to reduce ambiguity, the focusing adverb should be placed immediately before the item
Wáng Lín zhǐ zài bàngōngshì gěi tàitai dǎ le ge diànhuà.
(Wang Lin called his wife only from the office. (He didn’t call her from any other
Wáng Lín zài bàngōngshì zhǐ gěi tàitai dǎ le ge diànhuà.
(Wang Lin only called his wife from the office. (He didn’t call anybody else))
Wáng Lín zài bàngōngshì gěi tàitai zhǐ /dǎ le ge diànhuà/.
(Wang Lin only called his wife from the office. (He didn’t do anything else, such as
sending her an e-mail.))
Zhǐ Wáng Lín zài bàngōngshì gěi tàitai dǎ le ge diànhuà.
(Only Wang Lin called his wife from the office, i.e., other people didn’t.)
Focusing adverbials are most frequently placed before the item focused immediately. But some adverbs cannot occur before a pronoun or noun (e.g., ‘yě’(also), * ‘yě Wáng Lín’), so they are ordered before the predicate but as close to the item focused as possible. In such cases, we see that identification of the focused item is quite uncertain. However, written sentences do not occur in isolation any more than spoken sentences do, so when the context make a certain reading appropriate, we would unhesitantly read the sentence accordingly.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.