  Let M^n be a compact n-dimensional principal T^k-bundle. We consider
collapsings of M on N=M/T^k such that the diameter and sectional curvature of M
satisfy diam(M)<d and |K(M)|<a, and give examples of collapsings for all k such
that the first non-zero eigenvalue of Laplacian acting on 1-forms and 2-forms
of M are bounded above by c(M).inj(M)^2k. Moreover, we prove that the first
non-zero eigenvalue of 1-form Laplacian of all T^k-bundle M over N is bounded
below by c(n,d,a,N).Vol(M)^2 and c.inj(M)^2k when M collapses on N.
