acknowledge/ ək'nɔlɪʤ /

1.vt.[+fact] [ situation] [ problem] 
承认

2.vt.[+person met] 
对…打招呼

3.vt.[+letter] [ parcel] 
(by replying) 告知收到

4.vt.[+achievement] [ status] 
(recognize value of) 认可

to acknowledge that...
承认…