Contracts won in the year ended March include the Siemens Centre, Tong Zhoi IT Square and the Greenland Hyde Avenue Executive Condominium, all in Beijing, where the company has its China headquarters.   The group is “keeping an eye on opportunities for mergers and acquisitions in China to increase our competitiveness in the industry,” said CEO Edmond Mok to The Standard.   Examining possible expansion into inland cities such as Wuhan, Chongqing and Nanchang, the group is also in talks with developers for several mainland housing projects. Paul Y Engineering, a Hong Kong-based engineering servcies group owed by tycoon Charles Chan, has won contracts worth 4.5 billion HK dollars in the past year, the company told The Standard.