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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{15081fig2.ps} \end{figure}$	Figure 2: Zoom around the SO line 14₁₃-13₁₂ at 601.258 GHz. The other lines in the spectrum are from CH₃OH, CH₃OCH₃ as marked. Thre weaker lines are likely from ethanol (C₂H₅OH. Colours are as in Fig. 1. From bottom to top: L1157-B1, IRAS 16293-2422, OMC2-FIR4, AFGL 2591, and NGC 6334I.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{15081fig3.ps} \end{figure}$	Figure 3: Zoom around the HDO line 2_1,1-2_0,2 at 599.927 GHz and the H₂CO line 8_1,7-7_1,6 at 600.331 GHz. Colours are as in Fig. 1. From bottom to top: L1157-B1, IRAS 16293-2422, OMC2-FIR4, AFGL 2591, and NGC 6334I.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{15081fig4.ps} \end{figure}$	Figure 4: Zoom around the CH₃OH lines of the 12-11 series. The transitions of the brightest lines are marked following the JPL catalog. The DNC 8-7 line lies at 579.205 GHz. Colours are as in Fig. 1. From bottom to top: L1157-B1, IRAS 16293-2422, OMC2-FIR4, AFGL 2591, and NGC 6334I.
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Table 3: List of detected lines, for all species except CH₃OH and CH₃OCH₃.

Table 4: List of detected lines of CH₃OH.