Here's the answer:
“打电话问问”
(dǎ diàn-huà wèn-wen)
Watch a real native speaker say it:
Here's how it sounds in a textbook:
Fun fact: the hundreds of thousands of people learning Chinese with Memrise get this phrase correct 96.55% of the time!
(dǎ diàn-huà wèn-wen)
Fun fact: the hundreds of thousands of people learning Chinese with Memrise get this phrase correct 96.55% of the time!