liebe lily has altered a lot, so here I add.
他一月三号来了-----他一月三号要来。 要来-----means what will happen in the future.
我很久把它在等着。-----do you want to say 我等了他很久/我们等了他很久。。。I/we have been waitting for him for a long time.
还已经有三年的见识--- I guess you want to say 还有三年的工作经验。。。has/have three years' experience.
我去年十二月一号雇请了他----you can use 聘请 or 雇用.
in someplaces the words are very oral and not brief which we chinese may speak in that way in not normal palce and I think they are ok---such as <font color="#000000">他会说英语说得不错，学了数学和信息学学了很长时间; 我八点半给别的同事打电话</font>了; <font color="#000000">我认为今天十二月二十八号</font>(leave out 是); <font color="#000000">这样我们聊天了十五分钟。
my advices----1 notice the tense 2 practice more to make it closely to the way of chinese's, more accurate expressions are needed. it seems you have practiced more and it is not easy for a foreigner to learn well like you. go on to practice more to be better and better.
in all, GOOD JOB!</font>
