since you attach strace to a running process, you probably don't want to get the statistic report unless you don't mind to terminate that process. I guess that is what you refer to as "显示系统调用的花费时间". On command line, Generate Statistics Report of System Calls Using Option -c
However, you could try
Print Timestamp for Each Trace Output Line Using Option -t
It may not give you any clue since -t only counts up to second.
So try the following:
Print Relative Time for System Calls Using Option -r